Iontophoretic delivery of curcumin and curcumin analogs for the treatment of Alzheimer&#39;s disease

ABSTRACT

A device for iontophoretically delivering a charged curcuminoid across the skin of an Alzheimer&#39;s Disease patient.

CONTINUING DATA

This application is a continuation of copending U.S. Ser. No.12/147,881, entitled “Iontophoretic Delivery of Curcumin and CurcuminAnalogs for the Treatment of Alzheimer's Disease”, filed Jun. 27, 2008(Lillienfeld), the specification of which is incorporated by referencein its entirety.

BACKGROUND OF THE INVENTION

In Alzheimer's Disease (AD), the abnormal cleavage of beta amyloidprotein precursor from the intracellular membrane often produces aprotein Aβ 1-42 which is incompletely removed by normal clearanceprocesses. It has been reported that soluble beta amyloid oligomers arehighly neurotoxic. Moreover, over time, this soluble protein assemblageis deposited as a beta amyloid protein Aβ plaque within brain tissue,leading to the local destruction of neurons. The Aβ plaque deposition isalso believed to provoke an inflammatory response by microglia andmacrophages, which recognize the plaque as a foreign body. These cellsare believed to respond to the plaque deposition by releasingpro-inflammatory cytokines and reactive oxygen species (ROS). Althoughthe inflammatory response may be provoked in an effort to clear thebrain tissue of the detrimental plaque, it is now believed that thisinflammation also injures local neuronal tissue, thereby exacerbatingAD. Soluble oligomers of beta amyloid or “ADDLs” are a neurotoxicspecies implicated in AD pathogenesis. Yang, J. Biol. Chem., 280, 7,Feb. 18, 2005, 5892-5901.

In the book “The Memory Cure” (2003, McGraw-Hill, N.Y., N.Y.), Dr. MajidFotuhi writes: “Pharmaceutical companies in search of magic drugs totreat Alzheimer's Disease need to pay close attention to curcumin.”

It has been reported that 0.1-1.0 μM curcumin inhibits the in vitroformation of amyloid beta oligomers, and blocks the in vitro toxicity ofAβ₁₋₄₂ oligomers in differentiated neuroblastoma cells. Yang, J. Biol.Chem., 280, 7, Feb. 18, 2005, 5892-5901. Curcumin also reduced theamount of soluble beta amyloid by 43% when provided in the diet ofAlzheimer's Transgenic mice in a low dose of 160 ppm. Lim, J. Neurosci.,2001 Nov. 1, 21(21) 8370-7.

It appears that curcumin also beneficially reduces deposits of betaamyloid. In middle aged female Sprague-Dawley rats, 500 ppm dietarycurcumin reduced amyloid beta deposits induced by beta amyloid infusionby about 80%. Frautschy, Neurobiol. Aging, 22, 2001, 993-1005. Curcuminalso reduced beta amyloid plaque burden by about 30-40% when provided inthe diet of Alzheimer's Transgenic mice in a low dose of 160 ppm. Lim,J. Neurosci., 2001, Nov. 1, 21(21) 8370-7. This is advantageous becauseit is believed that the oxidative and inflammatory damage caused by ADis linked to microglial response to amyloid beta deposits.

In addition to its beneficial action against soluble beta amyloid,curcumin has considerable anti-oxidative properties and also inhibitsthe expression of pro-inflammatory cytokines. Frank, Ann. Clin.Psychiatry, 2005 October-Dec. 17, 4, 269-86, and Cole, Neurobiol. Aging,26S(2005) S133-S136.

Because curcumin is able to effectively act against many targets of AD,it has been hypothesized that the 4.4 fold lower incidence of AD in theIndian population between the ages of 70 and 79 is due to the highdietary consumption of curcumin. Lim, J. Neuroscience, Nov. 1, 2001,21(21) 8370-77. In those aged 80 years and older, age-adjustedAlzheimer's prevalence in India is roughly one-quarter the rates in theUnited States (4% versus 15.7%). Frautschy, Neurobiol. Aging, 22, 2001,993-1005. Curcumin has been identified in review articles as one of themost promising candidates for long term AD study. Frank, Ann. Clin.Psychiatry, 2005 October-Dec. 17, 4, 269-86, and Cole, Neurobiol. Aging,26S(2005) S133-S136. Curcumin is currently the subject of an FDAapproved IND clinical trial at the UCLA Alzheimer Center in thetreatment of mild to moderate AD patients. Cole, Neurobiol. Aging,26S(2005) S133-S136.

Because the above-mentioned in vivo effects of curcumin upon AD symptomswere achieved by providing curcumin in the diet, it appears thatcurcumin is effectively able to cross the blood brain barrier. Ascurcumin is highly lipophilic, it is expected to easily cross the bloodbrain barrier. Frautschy, Neurobiol. Aging, 22, 2001, 993-1005. Indeed,it has been reported that in vivo studies show that curcumin injectedperipherally into aged Tg mice crossed the blood brain barrier and boundamyloid plaques. Yang, J. Biol. Chem., 280, 7, Feb. 18, 2005, 5892-5901.

SUMMARY OF THE INVENTION

Despite the beneficial effects of curcumin, the present inventors havenoted that there are many bioavailability problems associated with theoral delivery of curcumin.

First, because curcumin does not easily penetrate the human digestivetract and is subject to intestine-based metabolism and rejection, lessthan 1% of oral curcumin enters the plasma. Second, the small amount ofcurcumin that enters the bloodstream is rapidly metabolized by the liverand kidney. Therefore, although curcumin is highly lipophilic (and soeasily crosses the blood brain barrier), only very small amounts oforally administered curcumin are registered in the serum and in thebrain tissue. One study found that ingesting up to 3.6 g of curcumin perday produced a plasma curcumin level in the range of only about 10 nM.Sharma, Clin. Cancer Res., 2004 Oct. 15, 10(20) 6847-54. A second studyfound that ingesting up to 6-8 g of curcumin per day produced a peakserum level in the range of about 0.51-1.77 μM. Third, it has beenreported that high oral doses of curcumin in the range of 4,000-8,000mg/day cause problems such as headache, rash and diarrhea, likelyproduced by metabolites of curcumin. Accordingly, it appears that theabove cited plasma curcumin concentrations (10 nM-1.77 μM) represent thepractical upper limit of oral dosing of curcumin. Yang, supra, concludesthat higher >(5 μM) concentrations of curcumin are not likely to occurin the brain with oral dosing. In fact, Wang reports that injection of30 mg/kg of curcumin results in a peak curcumin concentration in braintissue of only about 0.15 ng/mg, which is about 0.40 uM.

Moreover, patient safety concerns have recently been raised due to theability of oral curcumin to disable the drug-metabolizing enzyme systemsin the gut and liver of the patient: “Based on these data and expectedtissue concentrations of inhibitors, we predict that an orallyadministered curcuminoid/piperine combination is most likely to inhibitCYP3A, CYP2C9, UGT, and SULT metabolism within the intestinal mucosa.”Volak, Drug. Metab Dispos. 2008 May 14. Another investigator hasconcluded that “(Oaken together, the potential beneficial effects ofnatural antioxidants cannot justify the actual risk of severe sideeffects as well as the milder possibility of a ‘no effect’.” Mancuso,“Natural antioxidants in Alzheimer's disease”. Expert Opinion onInvestigational Drugs. December 2007, Vol. 16, No. 12, Pages 1921-1931.

It appears that, in the brain tissue concentration range about 1 uM,some but not all of the beneficial therapeutic qualities of curcumin arerealized. For example, it has been reported that 0.1-1.0 μM curcumininhibits the in vitro formation of amyloid beta oligomers, and blocksthe in vitro toxicity of Aβ₁₋₄₂ oligomers in differentiatedneuroblastoma cells. Yang, J. Biol. Chem., 280, 7, Feb. 18, 2005,5892-5901. However, there also appear to be a number of AD-relatedtherapeutic qualities of curcumin that are only realized at highercurcumin concentrations. For example, Yang reports that whereas 0.25-4uM concentrations of curcumin only minimally prevent the formation oftoxic beta amyloid oligomer formation in vitro, 16-64 uM concentrationsof curcumin completely prevent the formation of toxic beta amyloidoligomer formation. Yang also notes that curcumin has the pontential toinhibit copper binding of beta amyloid, but concludes that it is notclear whether curcumin's avidity for copper and potential concentrationin the brain will be enough to directly alter CNS beta amyloid metalbinding.

The present invention relates to the intranasal administration of aformulation comprising an effective amount of curcumin. In particular,the present invention relates to the intranasal administration of aformulation comprising an effective amount of curcumin to the olfactorymucosa across the cribriform plate and into the brain in order to treata neurodegenerative disease, such as AD.

The objective of the present invention is to improve curcumin brainbioavailability by administering curcumin via the nasal route in orderto deliver curcumin through the olfactory mucosa and to the brain, andto reduce the dose required for its beneficial effect. As curcumin ishighly lipophilic, it will easily pass through the olfactory mucosalocated high in the nasal cavity, and enter olfactory neurons andthereby the brain. This mode of delivery will also pass less curcumininto the circulation, and so will result in lower plasma concentrationsof metabolites of curcumin, and therefore fewer side effects. Intranasaldelivery will improve drug bioavailability to the brain by passivediffusion through the olfactory mucosa, thereby avoiding extensivehepatic first-pass metabolism which significantly lowers the plasma andbrain concentrations of curcumin administered orally. Therefore, smalldoses of curcumin can be administered which will result in fewer sideeffects, and the drug will be more tolerable and more effective.Lipophilic drugs such as curcumin generally achieve higher brain levelsafter intranasal administration than after oral or intravenousadministration. Therefore, the nasal route of administration of curcuminmay help to enhance the effectiveness of curcumin in the brain (the siteof action). Additionally, as curcumin is heavily metabolized by theliver, administration by the nasal route may help to reduce druginteractions with other drugs that are also extensively metabolized bythe liver. Lastly, because intranasally administered curcumin willpassively diffuse through the olfactory mucosa and into the olfactorybulb, which is connected to the hippocampus and amygdala through thelimbic system, it is believed that intranasal administration of curcuminwill preferentially deposit in the hippocampus and amygdala portions ofthe brain. These regions are believed to be origination sites ofAlzheimer's Disease.

Therefore, in accordance with the present invention, there is provided amethod for administering curcumin to a brain of a mammal, comprising:

-   -   a) applying a pharmaceutical composition comprising curcumin to        an upper third of a nasal cavity of the mammal, wherein the        curcumin is absorbed through an olfactory mucosa and transported        to the brain of the mammal.

DESCRIPTION OF THE FIGURES

FIGS. 1 a through 1 c disclose novel curcumin prodrugs of the presentinvention (1)-(30).

FIG. 1 d discloses preferred curcumin analogs (31)-(34) that arecandidate parent compounds for making prodrugs thereof.

FIGS. 2-16 disclose various curcumin derivatives that are hybrids ofcurcumin and various other natural polyphenols. Each of thesederivatives is a triphenolic compound, wherein the intermediate diketonestructure of curcumin is replaced with a phenolic group. The resultingcompound retains the spacing between the two phenols of curcumin, andalso possesses the biphenolic spacing of the additional polyphenol.

FIG. 2 discloses the structures of curcumin, resveratrol, and twocurcumin-resveratrol hybrids. Note how each of the hybrids retains theinterphenolic spacing of each of curcumin and reveratrol.

FIG. 3 discloses a method of making the curcumin-resveratrol I hybrid.

FIG. 4 discloses a method of making the curcumin-resveratrol II hybrid.

FIG. 5 discloses a method of making a curcumin-resveratrol hybrid havingthree hydroxyl groups in each of the central phenolic group and lateralphenolic groups.

FIG. 6 discloses curcumin, resveratrol and a hybrid thereof, wherein allof the phenolics of the natural compounds are represented in the hybrid,providing trihydroxyl lateral phenolic groups and a dihydroxyl centralphenolic group.

FIG. 7 discloses a method of making the curcumin-resveratrol hybrid ofFIG. 6.

FIG. 8 is similar to the hybrid of FIG. 6, but wherein the methoxygroups of the base curcumin molecule are retained.

FIG. 9 discloses curcumin, oxyresveratrol and a hybrid thereof, whereinall of the hydroxyls/phenolics of the natural compounds are representedin the hybrid, providing trihydroxyl lateral phenolic groups and atrihydroxyl central phenolic group.

FIG. 10 discloses curcumin, piceatannol and a hybrid thereof, whereinall of the hydroxyls/phenolics of the natural compounds are representedin the hybrid, providing trihydroxyl lateral phenolic groups and atrihydroxyl central phenolic group.

FIG. 11 discloses a method of making a curcumin-resveratrol hybrid,wherein all of the hydroxyls/phenolics of the natural compounds arerepresented in the hybrid, providing trihydroxyl lateral phenolic groupsand a dihydroxyl central phenolic group.

FIG. 12 discloses curcumin, BDMC, resveratrol and curcumin hybridsthereof, wherein all of the phenolics of the natural compounds arerepresented in the hybrid, providing hydroxyl demethoxy lateral phenolicgroups and a hydroxy or dihydroxyl central phenolic group.

FIG. 13 provides a method of making the compound of FIG. 12 that hashydroxyl demethoxy lateral phenolic groups and a hydroxy centralphenolic group.

FIG. 14 provides a method of making the compound of FIG. 12 that hashydroxyl demethoxy lateral phenolic groups and a dihydroxy centralphenolic group.

FIG. 15 discloses curcumin, piceatannol and a hybrid thereof, whereinmost of the hydroxyls of the natural compounds are represented in thehybrid, providing dihydroxyls in the end phenolic groups and a singlehydroxyl in the central phenolic group in the positions common with thetwo natural compounds.

FIG. 16 provides a method of making the compound of FIG. 15.

FIG. 17 discloses the structures of curcumin, 3,3′,4′ fisetin and acurcumin-3,3′,4′ fisetin hybrid, wherein all of the hydroxyls of thecurcumin and 3,3′,4′ fisetin compounds are represented in the hybrid,providing dihydroxyls in the end phenolic groups and a hydroxyl in theplace of each double bond.

FIG. 18 discloses a method of making the curcumin-3,3′,4′ fisetin hybridof FIG. 17.

FIG. 19 discloses the structures of curcumin, honokiol and acurcumin-honokiol hybrid, wherein all of the hydroxyls of the curcuminand honokiol compounds are represented in the hybrid, providing a singlehydroxyl in the end phenolic groups and a hydroxyl in the place of eachdouble bond.

FIG. 20 discloses a method of making the curcumin-honokiol hybrid ofFIG. 19.

FIG. 21 discloses a method of making a FIG. 13—honokiol hybrid, whereinall of the hydroxyls of the natural compounds are represented in thehybrid, providing single hydroxyl in the end phenolic groups in thepositions common with the two natural compounds, a hydroxyl in thecentral phenolic group, and a hydroxyl in the place of each curcumindouble bond.

FIG. 22 discloses a method of making a FIG. 15—3,3′,4′ fisetin hybrid,wherein all of the phenolics of the natural compounds are represented inthe hybrid, providing single hydroxyl in the end phenolic groups and ahydroxy central phenolic group in the positions common with the twonatural compounds, and an additional hydroxyl in the place of eachcurcumin double bond.

FIG. 23 discloses a typical iontophoresis system for delivering thecharged curcumin prodrugs of the present invention to an AD patient.

DETAILED DESCRIPTION OF THE INVENTION

As used herein curcumin is also known as diferuloylmethane or(E,E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione.Curcumin may be derived from a natural source, the perennial herbCurcuma longa L., which is a member of the Zingiberaceae family. Thespice turmeric is extracted from the rhizomes of Curcuma longa L. andhas long been associated with traditional-medicine treatments used inHindu and Chinese medicine. Turmeric was administered orally ortopically in these traditional treatment methods.

In some embodiments, curcumin is intranasally administered so that itproduces a brain tissue concentration of at least 0.1 μM, morepreferably at least 1 μM, more preferably at least 5 μM, more preferablyat least 20 μM.

Without wishing to be tied to a theory, it is believed that a dailyintranasal dose of at least about 0.2 mg/kg would be sufficient toproduce the above-cited brain tissue concentrations. More preferably,the dose is at least 1 mg/kg, more preferably at least 10 mg/kg.

It is believed that applying a pharmaceutical composition comprisingcurcumin at the above cited levels to an upper third of a nasal cavityof the mammal, wherein the curcumin is absorbed through an olfactorymucosa and transported to the brain of the mammal, will result inattainment of these higher levels of curcumin in brain tissue.

It is known that the more lipophilic a molecule, the greater itspropensity to cross the olfactory mucosa and the blood brain barrier. Inthis respect, it has been reported that the octanol:water partitioncoefficient of curcumin (log₁₀ PC) is 3.29. Therefore, curcumin is verylipophilic, and so should easily cross the olfactory mucosa and theblood brain barrier by passive diffusion.

It is further known that the blood brain barrier contains thep-glycoprotein (P-gp) transporter which effluxes a number of importantmolecules such as drugs. Accordingly, the behaviour of these pumpstowards curcumin is pertinent to the question of whether curcumin willcross the olfactory mucosa and the blood brain barrier. Since it hasbeen reported that curcumin lowers the expression of P-gp (Holland,Biochem. Pharmacol. 2006 Apr. 14, 71(8) 1146-54), it is believed thatcurcumin antagonizes these P-gp pumps. In addition to its ability tolower the expression of P-gp, it has been suggested that curcumin isable to modulate the function of hepatic P-gp. In both freshly-platedhepatocytes, containing low levels of Pgp, and 72 hour-culturedhepatocytes, containing high levels of Pgp, the Rhodamine-123 (R-123)efflux, which represents a specific functional test for Pgp-mediatedtransport, was inhibited by curcumin in a dose-dependent manner. (RomitiN, Tongiani R, Cervelli F, Chieli E. Effects of curcumin onP-glycoprotein in primary cultures of rat hepatocytes. Life Sci. 1998;62: 2349-58).

Because the octanol:water partition coefficient of curcumin (log₁₀ PC)is 3.29 and curcumin has been shown to antagonize P-gp, it is believedthat curcumin will easily cross the blood brain barrier. In thisrespect, it is helpful to compare these qualities of curcumin to thoseof hydroxyzine. It has been reported by Kandimalla, Int'l. J.Pharmaceutics, 302(2005) 133-144, that hydroxyzine.HCl has a molecularweight of 447.8, an octanol:water partition coefficient of log Doct/pH7.4 of only 2.37-2.87, and has the ability to inhibit P-gp. According toKandimalla, “the lipophilicity of (hydroxyzine), coupled with (its)ability to inhibit P-gp, enable(s) (it) to freely permeate across theolfactory mucosa.” Because curcumin has an even lower molecular weightthan hydroxyzine, has a significantly higher lipophilicity, and is ableto lower both the function and expression of p-gp, it is reasonablyconcluded that curcumin should be able to pass through the olfactorymucosa and the blood brain barrier even easier than hydroxyzine.

Since curcumin (MW=368) and carbamazepine (MW=236) have similarmolecular weights and are each highly lipophilic, the effects ofintranasal carbamazepine upon carbamazepine brain concentration arehighly instructive. Barakat, J. Pharm. Pharmacol., 2006 January 58(1)63-72 reports that peak brain tissue concentrations of carbamazepineattained by intranasal dosing (12 ug/g) were about four times higherthan those attained by oral dosing:

Carbamazepine Carbamazepine Peak Brain Route Dose (mg/kg) Tissue (ug/g)~uM Intranasal 0.2 12 48 Intravenous 8.0 4 16 Oral 16 3 12Therefore, if curcumin enters the brain in molar amounts similar tocarbamazepine (as is reasonably expected), then the resultingconcentrations may be sufficient to both completely prevent toxicoligomer formation and effect Aβ metal binding. If even higher dosagesof curcumin are used above 0.2 mg/kg, then the resultant brain tissueconcentration would be expected to be even higher.

The dose of curcumin can be combined with a mucoadhesive to enhance itscontact with the olfactory mucosa. In some embodiments, the mucoadhesiveis selected from the group consisting of a hydrophilic polymer, ahydrogel and a thermoplastic polymer. Preferred hydrophilic polymersinclude cellulose-based polymers (such as methylcellulose, hydroxyethylcellulose, hydroxy propyl methyl cellulose, sodium carboxy methylcellulose), a carbomer chitosan and plant gum.

In some embodiments, the mucoadhesive is a water-soluble high molecularweight cellulose polymer. High molecular weight cellulose polymer refersto a cellulose polymer having an average molecular weight of at leastabout 25,000, preferably at least about 65,000, and more preferably atleast about 85,000. The exact molecular weight cellulose polymer usedwill generally depend upon the desired release profile. For example,polymers having an average molecular weight of about 25,000 are usefulin a controlled-release composition having a time release period of upto about 8 hours, while polymers having an average molecular weight ofabout 85,000 are useful in a controlled-release composition having atime released period of up to about 18 hours. Even higher molecularweight cellulose polymers are contemplated for use in compositionshaving longer release periods. For example, polymers having an averagemolecular weight of 180,000 or higher are useful in a controlled-releasecomposition having a time release period of 20 hours or longer.

The controlled-release carrier layer preferably consists of awater-soluble cellulose polymer, preferably a high molecular weightcellulose polymer, selected from the group consisting of hydroxypropylmethyl cellulose (HPMC), hydroxyethyl cellulose (HEC), hydroxypropylcellulose (HPC), carboxy methyl cellulose (CMC), and mixtures thereof.Of these, the most preferred water-soluble cellulose polymer is HPMC.Preferably the HPMC is a high molecular weight HPMC, with the specificmolecular weight selected to provide the desired release profile.

The HPMC is preferably a high molecular weight HPMC, having an averagemolecular weight of at least about 25,000, more preferably at leastabout 65,000 and most preferably at least about 85,000. The HPMCpreferably consists of fine particulates having a particle size suchthat not less than 80% of the HPMC particles pass through an 80 meshscreen. The HPMC can be included in an amount of from about 4 to about24 wt %, preferably from about 6 to about 16 wt % and more preferablyfrom about 8 to about 12 wt %, based upon total weight of thecomposition.

Hydrogels can also be used to deliver the curcumin to the olfactorymucosa. A “hydrogel” is a substance formed when an organic polymer(natural or synthetic) is set or solidified to create athree-dimensional open-lattice structure that entraps molecules of wateror other solution to form a gel. The solidification can occur, e.g., byaggregation, coagulation, hydrophobic interactions, or cross-linking.The hydrogels employed in this invention rapidly solidify to keep thecurcumin at the application site, thereby eliminating undesiredmigration from the site. The hydrogels are also biocompatible, e.g., nottoxic, to cells suspended in the hydrogel. A “hydrogel-inducercomposition” is a suspension of a hydrogel containing desired curcumin.The hydrogel-inducer composition forms a uniform distribution of inducerwith a well-defined and precisely controllable density. Moreover, thehydrogel can support very large densities of inducers. In addition, thehydrogel allows diffusion of nutrients and waste products to, and awayfrom, the inducer, which promotes tissue growth.

Hydrogels suitable for use in the present invention includewater-containing gels, i.e., polymers characterized by hydrophilicityand insolubility in water. See, for instance, “Hydrogels”, pages 458-459in Concise Encyclopedia of Polymer Science and Engineering, Eds. Mark etal., Wiley and Sons, 1990, the disclosure of which is incorporatedherein by reference.

In a preferred embodiment, the hydrogel is a fine, powdery synthetichydrogel. Suitable hydrogels exhibit an optimal combination of suchproperties as compatibility with the matrix polymer of choice, andbiocompatibility. The hydrogel can include any of the following:polysaccharides, proteins, polyphosphazenes,poly(oxyethylene)-poly(oxypropylene) block polymers,poly(oxyethylene)-poly(oxypropylene) block polymers of ethylene diamine,poly(acrylic acids), poly(methacrylic acids), copolymers of acrylic acidand methacrylic acid, poly(vinyl acetate), and sulfonated polymers.Other preferred hydrogels include poly(acrylic acid co acrylamide)copolymer, carrageenan, sodium alginate, guar gum and modified guar gum.

In general, these polymers are at least partially soluble in aqueoussolutions, e.g., water, or aqueous alcohol solutions that have chargedside groups, or a monovalent ionic salt thereof. There are many examplesof polymers with acidic side groups that can be reacted with cations,e.g., poly(phosphazenes), poly(acrylic acids), and poly(methacrylicacids). Examples of acidic groups include carboxylic acid groups,sulfonic acid groups, and halogenated (preferably fluorinated) alcoholgroups. Examples of polymers with basic side groups that can react withanions are poly(vinyl amines), poly(vinyl pyridine), and poly(vinylimidazole).

Preferred thermoplastic polymers include PVA, polyamide, polycarbonate,polyalkylene glycol, polyvinyl ether, polyvinyl ether, and polyvinylhalides, polymethacrylic acid, polymethylmethacrylic acid, methylcellulose, hydroxypropyl cellulose, hydroxypropyl methylcellulose, andsodium carboxymethylcellulose, ethylene glycol copolymers.

Other polymers that may be suitable for use as a mucoadhesive includealiphatic polyesters, poly(amino acids), copoly(ether-esters),polyalkylenes oxalates, polyamides, tyrosine derived polycarbonates,poly(iminocarbonates), polyorthoesters, polyoxaesters, polyamidoesters,polyoxaesters containing amine groups, poly(anhydrides),polyphosphazenes, biomolecules (i.e., biopolymers such as collagen,elastin, bioabsorbable starches, etc.) and blends thereof. For thepurpose of this invention aliphatic polyesters include, but are notlimited to, homopolymers and copolymers of lactide (which includeslactic acid, D-, L- and meso lactide), glycolide (including glycolicacid), ε-caprolactone, p-dioxanone (1,4-dioxan-2-one), trimethylenecarbonate (1,3-dioxan-2-one), alkyl derivatives of trimethylenecarbonate, δ-valerolactone, β-butyrolactone, χ-butyrolactone,ε-decalactone, hydroxybutyrate, hydroxyvalerate, 1,4-dioxepan-2-one(including its dimer 1,5,8,12-tetraoxacyclotetradecane-7,14-dione),1,5-dioxepan-2-one, 6,6-dimethyl-1,4-dioxan-2-one, 2,5-diketomorpholine,pivalolactone, χ,χ-diethylpropiolactone, ethylene carbonate, ethyleneoxalate, 3-methyl-1,4-dioxane-2,5-dione,3,3-diethyl-1,4-dioxan-2,5-dione, 6,8-dioxabicycloctane-7-one andpolymer blends thereof. Poly(iminocarbonates), for the purpose of thisinvention, are understood to include those polymers as described byKemnitzer and Kohn, in the Handbook of Biodegradable Polymers, edited byDomb, et. al., Hardwood Academic Press, pp. 251-272 (1997).Copoly(ether-esters), for the purpose of this invention, are understoodto include those copolyester-ethers as described in the Journal ofBiomaterials Research, Vol. 22, pages 993-1009, 1988 by Cohn and Younes,and in Polymer Preprints (ACS Division of Polymer Chemistry), Vol.30(1), page 498, 1989 by Cohn (e.g. PEO/PLA). Polyalkylene oxalates, forthe purpose of this invention, include those described in U.S. Pat. Nos.4,208,511; 4,141,087; 4,130,639; 4,140,678; 4,105,034; and 4,205,399.Polyphosphazenes, co-, ter- and higher order mixed monomer-basedpolymers made from L-lactide, D,L-lactide, lactic acid, glycolide,glycolic acid, para-dioxanone, trimethylene carbonate and ε-caprolactonesuch as are described by Allcock in The Encyclopedia of Polymer Science,Vol. 13, pages 31-41, Wiley Intersciences, John Wiley & Sons, 1988 andby Vandorpe, et al in the Handbook of Biodegradable Polymers, edited byDomb, et al, Hardwood Academic Press, pp. 161-182 (1997). Polyanhydridesinclude those derived from diacids of the formHOOC—C₆H₄—O—(CH₂)_(m)—O—C₆H₄—COON, where m is an integer in the range offrom 2 to 8, and copolymers thereof with aliphatic alpha-omega diacidsof up to 12 carbons. Polyoxaesters, polyoxaamides and polyoxaesterscontaining amines and/or amido groups are described in one or more ofthe following U.S. Pat. Nos. 5,464,929; 5,595,751; 5,597,579; 5,607,687;5,618,552; 5,620,698; 5,645,850; 5,648,088; 5,698,213; 5,700,583; and5,859,150. Polyorthoesters such as those described by Heller in Handbookof Biodegradable Polymers, edited by Domb, et al, Hardwood AcademicPress, pp. 99-118 (1997).

In some embodiments, the mucoadhseive is selected from the groupconsisting of poly(lactic acid) (“PLA”) and poly(glycolic acid) (“PGA”),and copolymers thereof.

In some embodiments, the mucoadhesive formulation includes a penetrationenhancer such as sodium glycocholate, sodium taurocholate,L-lysophosphotidyl choline, DMSO and a protease inhibitor.

In some embodiments, the curcumin is tagged with a molecule that bindsspecifically with the olfactory mucosa, such as an odorant.

In some embodiments, the pharmaceutical composition comprising curcuminincludes a pharmaceutically-acceptable carrier, a lipophilic micelle, aliposome, or a combination thereof. Preferably, the lipophilic micelleor liposome comprises a ganglioside, a phosphatidylcholine, aphosphatidylserine, or a combination thereof.

In some embodiments, the pharmaceutical composition comprises asubstance having an affinity for a receptor site on a neuron.

According to particular methods of intranasal delivery, it can bedesirable to prolong the residence time of the pharmaceuticalcomposition in the nasal cavity (e.g., in the olfactory region and/or inthe sinus region), for example, to enhance absorption. Thus, thepharmaceutical composition can optionally be formulated with abioadhesive polymer, a gum (e.g., xanthan gum), chitosan (e.g., highlypurified cationic polysaccharide), pectin (or any carbohydrate thatthickens like a gel or emulsifies when applied to nasal mucosa), amicrosphere (e.g., starch, albumin, dextran, cyclodextrin), gelatin, aliposome, carbamer, polyvinyl alcohol, alginate, acacia, chitosansand/or cellulose (e.g., methyl or propyl; hydroxyl or carboxy;carboxymethyl or hydroxylpropyl), which are agents that enhanceresidence time in the nasal cavity. As a further approach, increasingthe viscosity of the dosage formulation can also provide a means ofprolonging contact of agent with olfactory epithelium. Thepharmaceutical composition can be formulated as a nasal emulsion,ointment or gel, which offer advantages for local application because oftheir viscosity.

The pharmaceutical composition can also optionally include an absorptionenhancer, such as an agent that inhibits enzyme activity, reduces mucousviscosity or elasticity, decreases mucociliary clearance effects, openstight junctions, and/or solubilizes the active compound. Chemicalenhancers are known in the art and include chelating agents (e.g.,EDTA), fatty acids, bile acid salts, surfactants, and/or preservatives.Enhancers for penetration can be particularly useful when formulatingcompounds that exhibit poor membrane permeability, lack oflipophilicity, and/or are degraded by aminopeptidases. The concentrationof the absorption enhancer in the pharmaceutical composition will varydepending upon the agent selected and the formulation.

To extend shelf life, preservatives can optionally be added to thepharmaceutical composition. Suitable preservatives include but are notlimited to benzyl alcohol, parabens, thimerosal, chlorobutanol andbenzalkonium chloride, and combinations of the foregoing. Theconcentration of the preservative will vary depending upon thepreservative used, the compound being formulated, the formulation, andthe like. In some representative embodiments, the preservative ispresent in an amount of 2% by weight or less.

The pharmaceutical composition can optionally contain an odorant, e.g.,as described in EP 0 504 263 B1 to provide a sensation of odor, to aidin inhalation of the composition so as to promote delivery to theolfactory epithelium and/or to trigger transport by the olfactoryneurons.

In some embodiments, the curcumin is delivered in a pharmaceuticalcomposition selected from the group consisting of a liquid, a powder, aspray, a nose drop, a gel, an ointment, or a combination thereof.

In some embodiments, the curcumin is delivered in a pharmaceuticalcomposition comprising piperine.

In some embodiments, the method of the present invention includesapplying the pharmaceutical composition to an olfactory area in theupper third of the nasal cavity, such as the olfactory mucosa. In someembodiments, the method of the present invention includes applying thepharmaceutical composition to a roof of a nasal cavity. In someembodiments, the method of the present invention includes applying thepharmaceutical composition by employing a tube, a catheter, a syringe, apacktail, a pledget, a submucosal infusion, an intranasal spraycontainer, or a combination thereof.

For delivery, there is provided a standard nose drops squeezable spraycontainer with a long thin semi-flexible tube attached to the distalend. The outer diameter of the tube is less than a millimeter,preferably less than 0.5 mm, more preferably less than 0.25 mm. The exithole of the tube is preferably located on the peripheral wall near thedistal end of the tube so that spray exiting it can be directed upwards.There is a marker on the container that indicates when the exit hole isoriented upwards towards the cribriform plate.

Therefore, in accordance with the present invention, there is providedan intranasal spray device comprising:

-   -   a) a hollow container having a first opening,    -   b) a flexible tube having a throughbore, a distal end portion        having a second opening, a proximal end having a third opening,    -   c) a formulation comprising an effective amount of curcumin        contained within the container,        wherein the third opening of the proximal end of the tube is in        fluid connection with the first opening of the hollow container.

In other embodiments, the intranasal spray device comprises:

-   -   a) a hollow container having a first opening,    -   b) a flexible tube having a throughbore, a side surface having a        second opening, a proximal end having a third opening, and a        distal end having an end surface,    -   c) a formulation comprising an effective amount of curcumin        contained within the container,        wherein the third opening of the proximal end of the tube is in        fluid connection with the first opening of the hollow container.

The user directs the tube towards the medial wall of the nostril andpoints upwards so as to direct it medially to and over the middle nasalconcha. The length of the tube is predetermined so that when the userhas the shoulder of the container flush against the nostril, the hole isadjacent the cribriform plate.

If there is concern about the safety of inserting a tube through a nasalpassage, then the tube can also be balloon-like, so that it expands tofull length upon being pressurized.

Delivery Through Anterior Nares

It has been reported that less than about 10% of inspired air travelsthrough the olfactory slit. Accordingly, a great deal of the curcumindelivered to the nasal cavity does not region the olfactory mucosa.Therefore, it is an object of the present invention to increase theamount of curcumin delivered to the olfactory mucosa.

It has been reported in the literature that when the airflow in thenasal cavity can be characterized as laminar, streamlines from theanterior 10% of the nares reach the olfactory slit.

Accordingly, in some embodiments of the present invention, at least 25%of the formulation comprising curcumin is delivered into the anterior10% of the nares. Preferably, at least 50% of the formulation comprisingcurcumin is delivered into the anterior 10% of the nares. Morepreferably, at least 75% of the formulation comprising curcumin isdelivered into the anterior 10% of the nares.

In some embodiments, focused delivery of the formulation into theanterior portion of the nares is assisted by providing a guidance tubelocated substantially in the anterior 10% of the nares.

In some embodiments, there is provided a device for assisting deliveryof a formulation to the anterior portion of the nares, comprising:

-   -   a) an annulus adapted to fit in the opening of the nares and    -   b) a guidance tube extending from the annulus and connected to        the annulus in the region of the anterior 10% of the nares.

As the streamlines just inside the opening of the nares travel at anangle of about 90 degrees, the guidance tube is preferably situated atthat angle in order to deliver the formulation into those streamlines.Preferably, the annulus is oval-shaped to correspond to the shape of thenares.

In use, the user simultaneously slowly inhales while actuating the spraycontainer containing the formulation. The formulation is delivered tothe anterior portion of the guidance tube as an aerosol in a laminarflow. The formulation travels through the guidance tube and exits isposterior end as an aerosol in a laminar flow. Thus, the formulationshould enter the nasal cavity in conformance with the laminarstreamlines of the inspired air produced by the inhalation. Once inthese streamlines, the formulation travels preferentially to theolfactory slit and thus to the olfactory mucosa.

Helium

In some embodiments, the curcumin is delivered to the olfactory mucosathrough helium-laden microbubbles that can rise in the air. This takesadvantage of the fact that the olfactory mucosa is located in thehighest portion of the nasal cavity. Theoretically, helium-filledmicrobubble of proper dimensions that are conventionally delivered intothe nasal cavity should travel upwards to the highest spot in the nasalcavity—the olfactory mucosa. Once they are in place, the microbubblescan be exploded with a simple hand held, non-invasive ultrasound device,thereby releasing their contents. This invention would greatly increasethe amount of curcumin that ends up in the olfactory mucosa.

Therefore, in accordance with the present invention, there is provided amethod for transporting a neurotherapeutic drug to a brain of a mammal,comprising:

-   -   a) applying a plurality of microbubbles comprising the        neurotherapeutic drug (preferably, curcumin), wherein the        microbubbles are lighter than air (and preferably contain helium        gas), to a nasal cavity of the mammal, whereby the microbubbles        rise to an upper third of a nasal cavity of the mammal,        whereupon the neurotherapeutic drug is absorbed through an        olfactory mucosa and transported to the brain of the mammal.

In other embodiments, the curcumin is delivered to the olfactory mucosaas an aerosol in a bolus of helium gas that can rise in the air. Thisalso takes advantage of the fact that the olfactory mucosa is located inthe highest portion of the nasal cavity. Theoretically, a helium bolusand the aerosols therein that are conventionally delivered into thenasal cavity should travel en masse to the highest spot in the nasalcavity—the olfactory mucosa. Once they are in place, the aerosols candeposit upon the nasal walls containing the olfactory mucosa. Thisinvention would greatly increase the amount of curcumin that ends up inthe olfactory mucosa.

Therefore, in accordance with the present invention, there is provided amethod for transporting a neurotherapeutic drug to a brain of a mammal,comprising:

-   -   a) providing a formulation comprising aerosol droplets of a        neurotherapeutic drug (preferably, curcumin) in a bolus of        helium gas, and    -   b) applying the formulation to a nasal cavity of the mammal,        whereby the formulation rises to an upper third of a nasal        cavity of the mammal, whereupon the neurotherapeutic drug is        absorbed through a nasal mucosa and transported to the brain of        the mammal.

US Patent Publication No. 2003/0199594 (“Shah”) discloses a propellantcomposition for use with an aerosol wherein the composition comprisesbetween 70% and 100% helium, wherein the composition may be used inintranasal spray devices such as metered dose inhalers. Shah disclosesthat the composition may further include a solvent (such as an alcoholsuch as ethanol) and a dispersing agent (such as oleic acid).

Therefore, in accordance with the present invention, there is providedan intranasal spray device having a formulation comprising:

-   -   a) an effective amount of curcumin, and    -   b) a propellant comprising helium (preferably, at least about        70% helium by weight), and    -   c) (optionally) a solvent (such as water or an alcohol such as        ethanol), and    -   d) (optionally)) a dispersing agent (such as oleic acid)        Curcumin Prodrugs

Although high lipophilicity in a therapeutic compound enables it toeasily cross the blood brain barrier and penetrate brain tissue, thathigh lipophilicity also usually means that the compound is not verysoluble in water. For example, US 2003/0153512 reports that lipophiliccurcumin has a solubility in water of only about 0.004 mg/ml. Becauseintranasal formulations are generally provided in small doses of between50 μl and 200 μl (typically, 100 μl), there may be an issue in providinga sufficient amount of the lipophilic compound in a single dose in orderto generate a therapeutic response.

Therefore, one aspect of the present invention involves providing thetherapeutic compound in the form of a water-soluble prodrug. The highwater solubility of the prodrug allows large amounts of it to beprovided in a single dose, enter the nasal mucosa and passively diffuseacross the nasal mucosa. Once the prodrug has reached the boundary ofbrain tissue, the prodrug is metabolized (typically through a chemicalor enzymatic hydrolysis reaction with brain esterases) to the parentlipophilic molecule, whereby it can diffuse into the brain tissue bulkand provide a therapeutic benefit.

Therefore, in accordance with the present invention, there is provided amethod for administering curcumin to a brain of a mammal, comprising:

-   -   a) applying a pharmaceutical composition comprising a water        soluble curcumin prodrug to an upper third of a nasal cavity of        the mammal, wherein the curcumin prodrug is absorbed through a        nasal mucosa and transported to the brain of the mammal.

In some embodiments, the parent lipophilic compound is a phenol that isrendered water-soluble by creating an ester having an added polar moietyor a permanent charge. Preferably, the ester has a polar moiety.Preferably, the polar moiety contains a tertiary or quaternary nitrogen.

Therefore, in some embodiments, the ester contains anaminoalkanecarboxylic acid as the polar moeity. These compounds arecharacterized by an ester moiety having an alkane group between thenitrogen compound and the carboxyl group. Preferably, the moiety hasterminal alkyl groups. More preferably, the aminoalkanecarboxylic acidcontains a glycinate moiety, more preferably a methylated glycinatemoiety, such as N,N, dimethylglycinate.

Therefore, in accordance with the present invention, there is provided acurcumin ester prodrug comprising an aminoalkylcarboxylic acid moeity.Preferably, the aminoalkylcarboxylic acid moiety comprises anaminoalkanecarboxylic acid moiety. In some embodiments, theaminoalkanecarboxylic acid contains a glycinate moiety. Methods ofmaking such compounds are found in Pop, Pharm. Res., Vol. 13(1) 1996,62-69.

Now referring to FIGS. 1 a-1 c, there are provided novel curcuminprodrugs of the present invention, labeled (1) to (30).

Therefore, in some embodiments, the aminoalkanecarboxylic acid moietycomprises a single terminal methyl group (1), two terminal methyl groups(2), (17), (20), or three terminal methyl groups (3)(19).

In some embodiments, the aminoalkanecarboxylic acid moiety comprises asingle terminal ethyl group (5), two terminal ethyl groups (6)(18), orthree terminal ethyl groups (8).

In some embodiments, the aminoalkanecarboxylic acid moiety comprises aterminal ethyl group and a terminal methyl group; a terminal ethyl groupand two terminal methyl groups (10); or two terminal ethyl groups and aterminal methyl group (9).

In some embodiments, the aminoalkanecarboxylic acid moiety comprises aterminal propyl group.

In some embodiments, the prodrug is in the form of a salt, as incompounds (3), (8)-(14), (17)-(20). Preferably, the salt comprises ananion selected from the group consisting of chloride (14)(17)(18)(20),iodide (19) and bromide.

In some embodiments, the prodrug is characterized by an ester moiety inwhich an ethane (17-18) or propane (19-20) group lies between thecarboxyl group and the nitrogen group, and preferably has a terminalalkyl group.

In some embodiments, the prodrug is characterized by an ester moiety inwhich the alkane that lies between the carboxyl group and the nitrogengroup is substituted. In some embodiments, this is a terminal ethylgroup (7) lying between the carboxyl group and the nitrogen group.Preferably, the moiety has a second terminal alkyl group.

In some embodiments, the curcumin prodrug comprises a carbamoyl moiety,preferably a (carboxymethyl)carbamoyl moiety (16). The(carboxymethyl)carbamoyl moiety of (16) can be made in substantialaccordance with Mulholland, Annals Oncology, 12, 245-8(2001).

In some embodiments, the aminoalkanecarboxylic acid moiety comprises anitrogen heterocycle (21,23). In some embodiments, the heterocyclecontain oxygen (23). Moeity (23) may be may in accordance with theprocedure disclosed in Pop, Pharm. Res., 13, 3, 469-475 (1996) andTrapani, Intl. J. Pharm., 175(1998) 195-204. Moeity (21) may be may inaccordance with the procedure disclosed in Trapani, Intl. J. Pharm.,175(1998) 195-204. Pop, Pharm. Res., 13, 3, 469-475 (1996) disclosesthat dexanabinol having a nitrogen heterocycle moiety like (21,23) has asolubility of about 5-7 mg/ml.

In some embodiments, the aminoalkanecarboxylic acid moiety comprises aL-proline group (15). Moeity (15) may be may in accordance with theprocedure disclosed in Altomare, Eur. J. Pharm. Sci., 20, 2003, 17-26and Trapani, Intl. J. Pharm., 175(1998) 195-204. Altomare reports thatthe L-proline ester of propofol provides the prodrug with a solubilityof about 1.1 mmol/ml.

In some embodiments, the aminoalkanecarboxylic acid moiety comprises abenzoate group (22). Moeity (22) may be made in accordance with theprocedure disclosed in Bundgaard, Pharm. Res., 8, 9, 1087-1093, (1991).Bungaard discloses that providing a benzoate moeity (22) between thecarboxyl and amino groups of a glycinate moiety raises the solubility ofAcyclovir from 1.4 mg/ml to 3 mg/ml at a pH of about 7, and to about 300mg/ml at a pH of about 5.

Other curcumin glycine esters are disclosed in Mishra, Bioorganic &Medicinal Chemistry, 13 (2005) 1477-86; Kumar, Nucleic Acids SymposiumSeries No. 44, 2000, pp. 75-76; Kapoor, Cancer Lett., 2007 Apr. 18,248(2) 245-50; Tong, Anti-Cancer Drugs 17(3) 279-187 March 2006; andMishra, Free Rad. Biology & Medicine, 38, (2005) 1353-1360

Desirable Prodrug Qualities

The curcumin prodrugs of the present invention should have threequalities: high solubility in water, high stability in water and rapidconversion to curcumin in the brain.

Solubility

The literature has demonstrated that glycinate-containing moietiesprovide much greater water solubility to phenolic compounds, typicallyincreasing the solubility of the parent compound to the 25-50 mg/mlrange. Examples of the solubility increase provided to low solubilityphenolics by their esterification by glycinates are as follows:

TABLE I Parent Ester Parent Solubility solubility Phenol (mg/ml) (mg/ml)Reference dexanabinol 2-7 ~50 (a) d-χ-tocopherol — ~25 (b) 17β-estradiol0.008 0.8-20 (c) testosterone 0.01  >100 (d) menahydroquinone — ~25 (e)phenol (+L-dopa) — 5 (f) (a) Pop, J. Pharm Sci, 88, 11, 1999, 1156 (b)Takata, J. Lipid Res., 2002, 43, 2196 (c) Al-Ghananeem, AAPSPharmSciTech, 2002, 3, 1, article 5 (d) Hussain, J. Pharm Sci., 91:785-789, 2002. (e) Takata, Pharm. Res., 21, 1, 1995, 18-23 (solubilityreported as 50 mM) (f) Kao, Pharm. Res., 17, 8, 2000, 978-984

It further appears that pH has a great influence upon the solubility ofnitrogen-containing esters of phenols. The influence of pH upon thesolubility of nitrogen-containing esters of phenols as reported in theliterature is presented below:

TABLE II ester solubility ester solubility at neutral pH at acidic pHParent (mg/ml) (mg/ml) Reference Propofol 0.064 4.67 (a) 0.735 6.920 (a)0.213 0.35 (a) Acyclovir 3 300 (b) (a) Trapani, Intl. J. Pharm.,175(1998) 195-204. (b) Bundgaard, Pharm. Res., 8, 9, 1087-1093, (1991).

The literature shows that, in most cases, providing the ester in anacidic pH (about 4-5) increases its solubility in water by about 10fold.

There also appears to be a special class of glycinate-like moieties thatincrease the water solubility of the phenolic compound even further. Inparticular, there are a number of glycinate-like moieties possessingadditional oxygens that increase the water solubility of the phenoliccompound to concentrations in the 100-1000 mg/ml range. Examples of suchcompounds are provided below:

Examination of these compounds reveals that each is characterized byterminal substitution of the amine by oxygen-containing moeities. Theyare particularly characterized by:

-   -   a) a (carboxymethyl) carbamoyl moiety (Mullholland, Ann.        Oncology, 12, 245-248 (2001)),    -   b) an N-acyloxymethyl moiety (Neilsen, Eur. J. Pharm. Sci., 2005        Apr. 24, 5, 433-40), or    -   c) a (oxyalkyl) acetamide moiety (U.S. Pat. No. 5,073,641),    -   d) glycine benzoates (WO90/08128)

Without wishing to be tied to a theory, it is believed that that thesemoieties may act as surfactants which, in the appropriate concentration,produce micelles. Indeed, it has been reported that a(dihydroxyethyl)glycinate moiety acts as a surfactant (U.S. Pat. No.6,831,108), and that the (carboxymethyl) carbamoyl moiety can producemicelles (Shamsi, Electrophoresis, 2005, 26, 4138-52). In oneembodiment, the prodrug moiety contains both a nitrogen and an terminaloxygen and forms a zwitterion.

Therefore, in accordance with the present invention, there is provided aformulation comprising a micellar curcumin prodrug.

The (carboxymethyl) carbamoyl moiety (Mullholland) is of particularinterest because is has a high solubility (>20 mg/ml). Its rapidhydrolysis in blood (t_(1/2)=0.39 hr) may indicate that it is alsorapidly hydrolyzed by brain esterases as well. Lastly, it appeats to berelatively stable in water (t_(1/2)=16.9 hr) and so likely is verystable in acidic aqueous solutions.

It has been reported that converting the prodrug into a salt likewiseincreases its solubility in water. For example, WO90/08128, whichrelates to glycine-like ester prodrugs, reports that conversion of suchprodrugs into salts produce water solubilities of up to 15 w/v %.Jensen, Acta Pharm. Nord., 3, (1) 31-40 (1991) reports that a dichloridesalt of one aminoalkylbenzoate ester was found to have a watersolubility of greater than 40% v/v at 20° C. Lastly, U.S. Pat. No.4,482,722 reports an addition salt of metrazole glycinate to have awater solubility of about 30%.

Stability

Because the formulations of the present invention are desirably used inthe form of aqueous-based nasal sprays, the ester prodrugs of thepresent invention should remain stable in water for an appreciable time.It appears that glycinate esters are much more stable in acidic aqueoussolutions than in neutral aqueous solutions. Al-Ghananeem, AAPS PharmSci Tech, 2002, 3, 1, article 5, reports that the stability of phenolesters is influenced by pH, that at slightly acidic pHs (pH 3-5), onephenol ester (17-DMABE₂HCl) would have sufficient shelf life to beformulated in a solution dosage form, and that a pharmaceutical nasalspray solution of the prodrug at pH 4 would have a shelf life ofapproximately 19 months at 25° C. Similarly, Kao, Pharm. Res., 17, 8,2000, 978-984 reports a maximum stability for the L-dopa butyl ester ata pH of 4.4, that the estimated time for 10% decomposition at pH 4.4,(0.05M phosphate buffer) and 10° C. is calculated to be 2.7 years, andthat at slightly acidic pHs (pH 3-5), the ester would have sufficientshelf-life stability to be formulated in a solution dosage form. Lastly,PCT Published Patent Application WO90/08128, which relates tobenzoate-containing glycine-like ester prodrugs, reports that onehydrocortisone-based prodrug possessed a shelf-life in aqueous solutionsof pH 4.0 of 6.0 and 10.2 years at 25° C. and 20° C., respectively.

Therefore, in some embodiments of the present invention, the curcuminformulation contains a buffer setting a pH of between about 3.0 and 5.5,preferably a pH of between about 3.5 and 5, preferably a pH of betweenabout 4 and 5. In some embodiments of the present invention, thecurcumin formulation contains a buffer setting a pH of between about 3and 4. It is believed that setting the pH of the formulation in theseranges would allow the formulations to have a commercially satisfactoryshelf life.

Also in some embodiments of the present invention, there is provided anintranasal spray device comprising a formulation comprising:

-   -   a) an effective amount of curcumin, and    -   b) a buffering agent setting a pH of between 3 and 5.5.        Conversion Rate

Once the prodrug has reached the brain, it is desirable for theesterified prodrug to be converted to its parent compound in a veryrapid fashion. Simply, the prodrug should be converted to the parentcompound by brain esterases before it is drained from the brain. Inorder to understand whether a prodrug converts sufficiently rapidly tothe parent compound, it is important to know the residence time of theprodrug in the brain or CSF.

Review of concentration versus time profiles of intranasally instilledcompounds reveals behaviours characterized by a two phase model. In thefirst phase, the drug rapidly attains a peak concentration and thenrapidly decreases to about 10-25% of the peak concentration within about1-2 hours. The second phase is characterized by a very slow decrease inthe concentration of the drug over the next 24 hours.

Therefore, if the concentration of the drug is approximated as thatwhich is present in the 1-2 hour range (i.e., about 10-25% of the peakconcentration), it can be assumed that the drug is present in the brainfor about 24 hours. Accordingly, in order to be useful, the conversionrate of the prodrug to the parent compound in the brain should becharacterized by a half-life t_(1/2) of no more than about 12 hours.

In at least three instances, the literature has reported conversionrates of a glycinate-containing phenolic ester to the parent compound bybrain homogenate. Two of these papers report very rapid conversion.Al-Ghananeem, AAPS Pharm Sci Tech, 2002, 3, 1, article 5, reports thatthe rapid conversion of estradiol glycinate esters to the parentestradiol in about 1-2 minutes. Kao, Pharm. Res., 17, 8, 2000, 978-984reports the rapid conversion of a benzyl L-dopa ester (wherein theL-dopa parent contains the glycinate moiety) in about 1 minute.

Since it is desirable to have a prodrug-to-parent conversion ratecharacterized by a half life t_(1/2) of no more than about 12 hours, andthe literature reports half-lives the rapid conversion of glycinateesters to the parent phenolic compound in about 1-2 minutes, it is clearthat glycinate prodrugs should be assumed to be fully converted in thebrain to the parent prodrug. It should be noted that one investigator(Trapani, Intl. J. Pharm., 175(1998) 195-204) reports a much slowerconversion of propofol glycinate ester to the parent propofol. However,review of the pertinent structure-activity relationships indicates thatthe hydroxyl moiety of the propofol is severely sterically hindered byadjacent isopropyl groups of the propofol. Without wishing to be tied toa theory, it is believed that the severe steric hinderance of theetheric oxygen of these propofol glycinates is the reason for its slowconversion from the glycinate ester to propofol.

In contrast, the etheric oxygen of both benzyl L-dopa ester and theestradiol glycinate ester experiences much less steric hinderance, andso the brain esterase has an opportunity to freely approach the ethericoxygen from at least one side of the molecule. As a result, thehydrolysis reaction by brain esterases can occur much more quickly.

Undertaking a similar analysis with curcumin glycinate esters revealsthat, like L-dopa and estradiol, the curcumin glycinate esterexperiences much less steric hinderance, and so the brain esterases havethe opportunity to freely approach the etheric oxygen of the curcuminglycinate ester from at least one side of the molecule.

Moreover, it appears that another research group reports a much fasterconversion of the propofol dimethyl glycinate ester to the parent andthat the Trapani group has acknowledged this difference. See Altomare,Eur. J. Pharm. Sci., 20, 2003 17-26.

Lastly, the Kao paper is noteworthy in that it reports highly similarhalf-lives for the conversion of L-dopa esters to L-dopa in brainhomogenate and plasma. A high coincidence of half-lives for theconversion of propofol glycinate esters to propofol in brain homogenateand plasma is also reported in Trapani. If conversion in plasma is usedto reasonably estimate the conversion of glycinate esters in brainhomogenate, then the literature may be further consulted for theconversion of glycinate-containing phenolic esters to the parentphenolic compound in plasma. The literature, reported below in TableIII, reports the following:

TABLE III Half-life Of glycinate ester Parent Compound In plasma (min)Reference Dexanabinol 0-26 (a) Phenol (+L-dopa) 0.36 (b) Acyclovir 0.8(c) Estradiol 1-2 (d) Propofol 24 hrs (e) Menahydroquinone 13 (f) (a)Pop, J. Pharm. Sci., 88, 11, 1999, 1156 (b) Kao, Pharm. Res., 17, 8,2000, 978-984 (c) Bundgaard, Pharm. Res., 8, 9, (1991) 1087-1093 (d)Al-Ghananeem, AAPS PharmSciTech, 2002, 3, 1, article 5 (e) Trapani,Intl. J. Pharm., 175(1998) 195-204 (f) Takata, Pharm. Res., 21, 1, 1995,18-23

Thus, using literature reports of conversion in plasma to reasonablyestimate the likely conversion window of glycinate esters in brainhomogenate, it appears that the conversion of glycinate-containingphenolic esters to the parent phenolic compound in brain is again quiterapid.

Therefore, because unhindered phenolic glycinate esters rapidly convertto the parent phenol in brain homogenate, and because dimethylglycinatephenolic esters convert rapidly in plasma, it is believed that theconversion rates of glycinate-containing curcumin esters to the parentcurcumin compound will be rapid in a brain environment.

How to Make Prodrugs

Al-Ghananeem, AAPS Pharm Sci Tech, 2002, 3, 1, article 5, teaches how tomake an ester comprising the following amino-alkane-carboxylic acidmoieties: 3-N,N dimethylamino butyl ester HCl (3-DMABE₂HCO;3-N,N-diethylamino propionyl ester hydrochloride (DEAPE₂HCl);3-N,N,N-trimethylamino butyl ester iodide (3-TMABE₂ iodide) and 17-N,Ndimethylamino butyl ester HCl (17-DMABE₂HCl);

In some embodiments, the water-soluble ester prodrug is created byreacting the phenolic parent compound with dimethylglycine. Theliterature reports rendering lipophilic phenolic compounds water solubleby reacting the phenolic parent compound with dimethylglycine. Forexample, Al-Ghananeem, AAPS Pharm Sci Tech, 2002, 3, 1, article 5,reports increasing the water solubility of 17B-estradiol from 0.008mg/ml to 0.8 mg/ml (a 100-fold increase) by creating a dimethylglycineester of the parent compound. Al-Ghananeem further found that this esterwas readily hydrolyzed by rat brain homogenate to provide the parentcompound, and that intranasal administration of the prodrug provided a5-8 fold higher CSF concentration of 17B-estradiol when compared with acomparable intravenous dose of the prodrug. Al-Ghananeem concluded thatthe prodrug provides for targeted intranasal delivery of 17B-estradiolto the brain.

In some embodiments, creation of the water soluble ester prodrug fromthe parent phenolic compound is carried in substantial accordance withthe method described in Hussain, J. Pharm. Sci., 91, 3 Mar. 2002,785-789. In particular, dimethylglycine HCl and oxalyl chloride aregently warmed at 40° C. until evolution of HCl gas ceases. Nitrogen gasis then bubbled through the solution to remove unreacted oxalylchloride. The resulting acid chloride is dissolved in dimethylformamideand added dropwise with stirring to a solution of the parent phenoliccompound in methylene chloride. The reaction mixture is refluxed for 3hours. The ester is then isolated, and converted to an HCl salt.

In some embodiments, creation of the water soluble ester prodrug fromthe parent compound is carried in substantial accordance with the methoddescribed in Al-Ghananeem, AAPS Pharm Sci Tech, 2002, 3, 1, article 5.In particular, 4-(dimethylamine) butyric acid hydrochloride (2.0 g,0.012 mol) or 3-(dimethylamine)proprionic acid hydrochloride (2.2 g,0.012 mol) is used as a starting material. The amino acid is refluxedgently with oxalyl chloride (1.6 mL, 0.018 mol) for a short period oftime until a clear yellow solution is formed. The solution mixture isthen flushed very gently with a stream of nitrogen to remove excessoxalyl chloride leaving a solid behind (the acid chloride).

The phenolic esters having 3-N,N-dimethylamino butyl ester hydrochloride(3-DMABE₂HCl); 3-N,N-dimethylamino propionyl ester hydrochloride(3-DEAPE₂HCl); and 3-N,N,N-trimethylamino butyl ester iodide (3-TMABE₂iodide) as moieties are synthesized after the appropriate acid chloridefollowing the procedure reported in Hussian, Pharm. Res., 1988, 5, 1,44-47. The alcoholic ester, 17-N,N-dimethylamino butyl esterhydrochloride (17-DMABE₂HCl) is prepared by dissolving the acid chlorideslowly in 10 mL N,N, dimethylformamide (DMF) while in an ice bath sincethe reaction is exothermic. The parent phenolic compound is thendissolved in methylene chloride, and the DMF solution of acid chloridewas added dropwise to the solution of the parent phenolic compound withstirring; The reaction mixture is refluxed gently for 45 minutes, thenfiltered. The filtrate is evaporated using a Buchi model rotavaporator(Westbury, N.Y.) then redissolved in a small volume of 80 CHCl₃: 20MeOH. The content of the mixture is separated and purified using asilica gel column. The solvent mixture is evaporated and the productredissolved in a small volume of methylene chloride, then hydrogenchloride gas is carefully bubbles through the solution with stirring.The ester hydrochloride is precipitated by adding enough diethyl etherto make the solution turbid and then the mixture is placed in arefrigerator at 4° C. overnight. The final product is collected bysolvent evaporation in a vacuum dessicator using a Precision Scientificmodel D75 pump (Chicago, Ill.) at room temperature and stored in adesiccator until used.

In some embodiments, creation of the water soluble ester prodrug fromthe parent compound is carried in substantial accordance with the methoddescribed in Takata, J. Lipid Res., 2002, 43, 2196-2204. In particular,to a dry pyridine solution of the parent phenolic compound (4.8 mmol),5.7 mol of N,N-dimethylglycine HCl and 5.7 mmol ofdicyclohexylcarbodiimide are added. The reaction mixture is stirred atroom temperature for 20 hours and the dicyclohexylurea formed is removedby filtration. After the solvent is evaporated, the residue is treatedwith 100 ml of water and made alkaline by sodium bicarbonate. Thesolution is then extracted with ethyl acetate (100 ml×3). The organiclayer is dried over anhydrous sodium sulfate with ethyl acetate andevaporated. The residue is fractionated with a flash column packedWakogel LP40, 60A using n-hexane ethyl acetate (8:2, v/v) as the eluent.The isolated ester is directly collected in isopropyl ether containing3% HCl dioxane solution, and the precipitate and recrystallized fromacetone to give the HCl salt of the parent phenolic compound.

Brain Levels

Evidence that the intranasal installation of a water soluble prodrug ofcurcumin can deliver high levels of curcumin to the brain is found inthe estradiol-based work of Al-Ghananeem, AAPS Pharm Sci Tech, 2002, 3,1, article 5. 17β-Estradiol is a 272 dalton phenol having aoctanol/water partition coefficient of about log P=3.1-4.0. Therefore,estradiol is similar to curcumin in that each is a lipophilic, phenolicsmall molecule. Also, like curcumin, 17β-estradiol also suffers frompoor bioavailability. Moreover, Al-Ghananeem reports that estradiol isnot very soluble in water, thereby making impractical the nasaladministration of an effective dose (0.1 mg in 0.1 ml). Al-Ghananeemreports modifying estradiol with a dimethylglycinate moiety to increasethe water solubility of estradiol from 0.008 mg/ml to about 0.8 mg/ml-a100-fold increase, and modifying estradiol with a 3-DEAPE₂HCl moiety toincrease the water solubility of estradiol from 0.008 mg/ml to about 20mg/ml-over a 1000 fold increase. Thus, the solubility of a lipophilic,phenolic small molecule like curcumin, which has a solubility in waterof only about 0.004 mg/ml, can be greatly increased.

Because the typical volume of an intranasal dose for a human can be upto 0.2 ml, and Table I above reports increases in solubility in therange of 20 mg/ml, nasal administration can be expected to achieve apayload of up to about 20 mg/ml×0.2 ml=4 mg/dose. Because providing twodoses per nostril twice a day provides 8 doses per day, it is believedthat up to about 32 mg/day of estradiol can be intranasallyadministered. This amount provides a whole body concentration of nearlyabout 0.5 mg/kg.

Further, Al-Ghananeem reports that the nasal installation of 0.1 mg/kgof water soluble prodrugs of 17β-Estradiol results in peak cerebrospinalfluid (CSF) concentrations of estrdiol of between about 30 ng/ml (for17-DMABE₂-HCl) to about 66 ng/ml (for 3-DMABE₂-HCl), which provides amolar concentration of the compound of between about 0.075 μM and 0.15μM. The pharmacokinetic results of Al-Ghananeem correspond quite wellwith those of Kao, who reported that nasal installation of 20 mg/kg ofwater soluble ester prodrug of L-dopa results in peak cerebrospinalfluid (CSF) concentration of about 10-20 ug/ml. Accordingly, a 0.5 mg/kgnasal instillation of a water soluble prodrug of a lipophilic, smallmolecule phenolic compound such as estradiol or curcumin can likelyprovide CSF concentrations of up to about 0.75 μM. Since it has beenreported that 0.1-1.0 μM curcumin inhibits the in vitro formation ofamyloid beta oligomers, and blocks the in vitro toxicity of Aβ₁₋₄₂oligomers in differentiated neuroblastoma cells (Yang, J. Biol. Chem.,280, 7, Feb. 18, 2005, 5892-5901), it appears that the intranasalinstallation of a water soluble prodrug of curcumin will likely allow anattainable dosing schedule to attain a brain concentrations of curcuminthat will provide a therapeutic benefit against Alzheimer's Disease.

Dual Phase Curcumin

In some embodiments, curcumin is present within two separate phases ofthe formulation. The first phase is preferably a quick release phasethat quickly delivers curcumin to the olfactory mucosa. The quickdelivery of curcumin will have the effect of transiently disablingenzymes systems such as UGTs and P450s that metabolize curcumin. Thesecond phase is a slow release phase that slowly delivers curcumin tothe olfactory mucosa. Once these enzyme systems are transientlydisabled, the slow release phase slowly releases curcumin in anenvironment that is substantially free of enzymatic metabolicinterference.

Therefore, in accordance with the present invention, there is provide aformulation comprising:

-   -   a) a first, quick release phase comprising an effective amount        of curcumin for transiently disabling enzyme systems, and    -   b) a second slow release phase comprising an effective amount of        curcumin for treating a neurodegenerative disease.        In some embodiments, the first quick release phase can be        selected from the group consisting of a mucoadhesive and an oil,        such as peppermint oil. Peppermint oil has the quality of        independently inhibiting UGT and P450 enzymes.        In some embodiments, the second slow release phase can be        selected from the group consisting of liposomes and        thermoplastic polymers (such as PLGA).

In accordance with the present invention, there is provided aformulation comprising:

a) a polymeric particulate depot comprising curcumin, and

b) a mucoadhesive.

In some embodiments, the mucoadhesive is present as a coating upon thepolymeric particulate depot.

In some embodiments, the mucoadhesive is present as a separateparticulate.

In some embodiments, the mucoadhesive comprises a compound selected fromthe group consisting of a chitosan and a cellulose.

In some embodiments, the mucoadhesive further contains curcumin.

In some embodiments, the polymeric particulate depot is a liposome.

In some embodiments, the polymeric particulate depot is a thermoplasticbioresorbable polymer.

In some embodiments, the curcumin is housed in microspheres. Kumar,Indian J. Physiol. Pharmacol., 2002 April 46(2) 209-17 reports that whencurcumin was loaded into either albumin or chitosan microspheres, abiphasic release pattern occurred, characterize by a burst effectfollowed by a slow release. This biphasic effect corresponds well withthe stated desire to have a first dose of curcumin released in order toinhibit enzyme activity in the olfactory mucosa followed by a seconddose that is slowly released, taken up by the olfactory neurons andtransported to the brain. In some embodiments, the curcumin is housed inmicrospheres that display a biphasic release effect.

Enzyme Inhibition by Curcumin

Although curcumin is susceptible to metabolism by enzymes, curcumin isalso known as an inhibitor of those very enzymes. For example, Hong,Biochem. Biophys. Res. Comm., 2003 Oct. 10, 310(1) 222-7, reports thatco-treatment by curcumin of EGCG in cells transfected with hPgP, hMRP1and hMRP2 genes increased the accumulation of EGCG in those cells.

It has been reported that curcumin influence both multidrug resistanceprotein 1 (MRP1) multidrug resistance protein 2 (MRP2). It appears thatcurcumin inhibited both MRP-1 and MRP-2-mediated transport with IC₅₀values of 15 uM and 5 uM. Wortelboer, Chem. Res. Toxicol., 2003 Dec. 16:12, 1642-51. Wortelboer also recognized the “complex interplay betweenMRP inhibition and metabolism of MRP inhibitors. Chearwae, CancerChemother. Pharmacol., 2006 February 57(3) 376-88 reports curcumin toinhibit MRP1, with an IC50 of about 14.5 uM.

Of note, Hong, Biochem. Biophys. Res. Comm. 2003 Oct. 10, 310(1) 222-7reports that the inhibition of MRPs by curcumin led to a significantincrease in the amount of green tea catechin EGCG in MDCKII/MRP1 andHT-29 cells. Therefore, there is a special advantage in providing bothcurcumin and EGCG in the same formulation, as curcumin can providetherapeutic benefits and increase the bioavailability of EGCG.

It appears that curcumin is metabolized mainly through glucuronidation.Pan, Drug Metab. Dispos., 1999, 27, 1, 486-494. However, it has beenrepeatedly demonstrated that curcumin also inhibits glucuronidation.Basu, Drug. Metab. Dispos., 2004 July 32(7) 768-73 reports that curcumintransiently inhibits MPA glucuronidation in both human LS180 colon cellsand mouse duodenum. Basu, PNAS, May 3, 2005, 102(18) 6285-90 reports theinhibition of cellular UGT1a7 and UGT1A10 activities after exposure tocurcumin. Basu, J. Biol. Chem., 279, Jan. 9, 2004, 1429-1441 reportsthat curcumin reversible targets UGTs causing inhibition. In general,curcumin appears to provide its maximum inhibition of UGT activity about1-2 hours after exposure. Basu, Biochem. Biophys. Res. Comm., 303(2003)98-104 (FIG. 1) reports that the inhibition of UGT1A1 by curcumin canreach about 95% after about one hour after exposure, returning to about80% of the control value after about 10 hours. Naganuma, Biol. Pharm.Bull., 2006 July 29(7) 1476-9 reports the moderate inhibition of UGTactivity in the conjugation of 1-naphthol in Caco-2 cells by curcumin.

Because of the strong inhibition of UGTs by curcumin, curcumin has beenproposed as a pre-treatment for cancer chemotherapy, and it has beenreported that transient inhibition of glucuronidation by oralpretreatment with curcumin before MPA administration caused a six-foldincrease in immunosuppression of antigen-stimulated spleen cytotoxicT-lymphocyte proliferation in mice. See(http://nichddirsage.nichd.nih.gov:8080/ar2004/pages/hdb/sgddm.htm).

There is, however, one investigator (van der Logt, Carcinogenesis, 24,10, 1651-56, 2003) that reports enhancement of UGT activity by curcumin.

Because the glucuronidation inhibition by curcumin is reversible, itappears that curcumin could be used for a pre-treatment of the olfactorymucosa in order to inhibition enzymatic activity upon the latertherapeutic dose of curcumin without a concern for drug-druginteractions.

Therefore, in some embodiments, a first dose of curcumin is intranasallyadministered to the patient (to inhibit enzyme activity in the olfactorymucosa), and then a second dose of curcumin is intranasally administeredto the patient at least about 15 minutes after the first dose (to travelto the brain).

It is well known that that the cytochrome p450 enzymes are significantin the olfactory mucosa. Oetari, Biochem. Pharmacol., 1996 Jan. 12,51(1) 39-45 reports that curcumin strongly inhibits P450s in rat liver.Thapliyal, Food Chem. Toxicol. 2001 June 39(6) 541-7 reported theinhibition of cytochrome P450 isoenzymes by curcumins both in vitro andin vivo.

Zhou, Drug Metab. Rev., 2004 February 36(1) 57-104 reports curcumin tobe an inhibitor of Pgp.

In some embodiments, piperine is used as a glucuronidation inhibitor.Reen, Biochem. Pharmacol., 1993 Jul. 20, 46(2) 229-38 reports piperineto be a potent inhibitor of glucuronidation. Shoba, Planta Med., 1998May 64(4) 353-6 reports that pre-administration of piperine led to a2000% increase in the bioavailability of curcumin in humans.

In some embodiments, the glucuronidation inhibitor is an analog ofpiperine. Preferably, the piperine analog is antiepilepsirine.Administration of antiepilepsirine is also effective in raisingserotonin synthesis (Liu, Biochem. Pharmacol., 1984 Dec. 1, 33(23)3883-6), and has been studied as an antiepilepsy drug (Wang, Brain Dev.1999 January 21(1) 36-40). Accordingly, its intranasal administrationshould not lead to significant problems.

In some embodiments, the glucuronidation inhibitor is a surfactant.Kurkela, J. Biol. Chem., 2003 Feb. 7; 278(6) 3536-44 reports thatseveral UGT enzymes were nearly fully inhibited by a surfactant, namelyTriton X-100. Preferably, the surfactant is a non-ionic surfactant.

In some embodiments, the glucuronidation inhibitor is a mucolytic agent,such as N-acetylcysteine (NAC). Takatsuka, Int. J. Pharm., 2006 Jun. 19,316(1-2) 124-30, reports that co-administration of a mucolytic agent(NAC) and a surfactant (Triton TX-100) led to enhanced intestinalabsorption in a synergistic manner. It was further reported that thedamage to the mucosa was reversible.

In some embodiments, the glucuronidation inhibitor is an NSAID. Inpreferred embodiments, the NSAID is niflumic acid. Mano, Biopharm. DrugDispos., 2006 January, 27(1) 1-6 reports the inhibitory effect ofNSAIDs, and niflumic acid in particular, on UGT activity.

Enzyme Inhibition by Buffer

In some embodiments, low pH buffers are used as glucuronidationinhibitors. Basu, PNAS, May 3, 2005, 102, 18, 6285-90 reports maximumglucuronidation of lipophiles by UGT in the pH range of 6-9, and nearlyzero glucronidation activity by UGT at pH 5. Similarly, Basu, J. Biol.Chem., 279, Jan. 9, 2004, 1429-1441 reports that pH can drasticallyalter the level of UGT activity, and that a pH of 5 inhibits nearly allglucuronidation activity for each of UGT1A7 and UGT1A10. Therefore, itappears that low pH formulations are effective in completely inhibitingglucuronidation activity. In some embodiments of the present invention,the curcumin formulation contains a buffer setting a pH of between about3.0 and 5.5, preferably a pH of between about 3.5 and 5, preferably a pHof between about 4 and 5. In some embodiments of the present invention,the curcumin formulation contains a buffer setting a pH of between about3 and 4. Below these cited ranges, there is a chance that the acidicnature of the formulation will be irritating to the nasal cavity. Abovethis range, there may be minimal inhibition of glucronidation. U.S. Pat.No. 6,187,332 (“Gern”) discloses a buffered flowable nasal sprayformulation having a pH of between 4 and 5 which is able to maintain itspH for prolonged periods in the human nose. Gem discloses formulationcomprising citrate and phosphate buffering agents.

Therefore, in accordance with the present invention, there is providedan intranasal spray device comprising a formulation comprising:

-   -   a) an effective amount of curcumin, and    -   b) a buffering agent (preferably, a citrate or phosphate) having        a pH of between 4 and 5 which is able to maintain the pH of the        formulation between 4 and 5 in the human nose for prolonged        periods.        Absorption Enhancers

In some embodiments, the absorption enhancer is a bile salt.Chavanpatil, Pharmazie, 2005 May, 60(5) 347-9. In preferred embodiments,the bile salt is selected from the group consisting of sodiumdeoxycholate, sodium caprate, and sodium tauroglycocholate and EDTA.

In some embodiments, magnesium⁺² is used as a glucuronidation inhibitor.Wong, Biochem. J., (1968) 110, 99 reports that Mg⁺² concentrations inexcess of about 10 mM were effective in inhibiting about 85% ofenzymatic glucuronidation activity.

Cooling

It is appreciated by the inventors that the UGT enzyme is likely verysensitive to temperature. Therefore, it is reasonable to expect that adecrease in the temperature of the mucosal lining will result in adecrease in the enzymatic glucuronidation of curcumin by the UGTs.Indeed, it has been reported by Castuma, Biochem. J., (1989) 258,723-731 that the enzymatic activity of UDP-glucuronyltransferase innormal liver microsomes of guinea pigs decreased about 3-fold when thetemperature of the microsomes was reduced from about 37° C. to about 10°C.

Therefore, the present inventors have devised inventions based upon thetemporary cooling of the nasal mucosa in order to inhibit theglucuronidation of curcumin.

In one embodiment, the formulation of the present invention contains acooling agent such as menthol.

In one embodiment, the formulation of the present invention contains anendothermic solute. In preferred embodiments, the endothermic solute isa strong salt, acid or base that dissolves in water by an endothermicprocess. More preferably, the endothermic solute is a salt.

In some embodiments, the endothermic solute may be selected from thegroup consisting of sodium bicarbonate (ΔH=+19.1 kJ/mol); potassiumbicarbonate (ΔH=+5.3 kcal/mol); potassium sulfate (ΔH=+23.7 kJ/mol);potassium chloride (ΔH=+17.2 kJ/mol); sodium chloride (ΔH=+3.9 kJ/mol);and potassium dihydrogenphosphate (ΔH=+19.6 kJ/mol).

In some embodiments, the endothermic solute may be magnesium sulfate,which would both promote cooling and inhibition glucuronidation.

Therefore, in accordance with the present invention, there is providedan intranasal spray device comprising a formulation comprising:

a) an effective amount of curcumin, and

b) an endothermic solute (preferably magnesium sulfate)

It is well known that curcumin is poorly soluble in water. Because theolfactory mucosa is aqueous-based, the transport of curcumin from theformulation across the olfactory mucosa is problematic.

Therefore, in order to increase the transport of curcumin across theolfactory mucosa, in some embodiments, the curcumin is delivered in aformulation comprising an effective amount of a curcumin-misciblesolvent. Preferably, the solvent is selected from the group consistingof DMSO and ethanol. It is well known that curcumin is highly soluble inDMSO and ethanol. When this formulation is applied to the nasal mucosa,the solvent mixes with the water in the olfactory mucosa and renderscurcumin soluble in that mixture.

In preferred embodiments, the solvent is DMSO. DMSO is non-toxic andalso can temporarily open the blood brain barrier. Kleindienst, ActaNeurochir. Suppl. 2006; 96, 258-62, and Scheld, Rev. Infect. Dis., 1989November-Dec. 11 Suppl 7; S1669-90.

Therefore, in accordance with the present invention, there is providedan intranasal spray device comprising a formulation comprising:

a) an effective amount of curcumin, and

b) a solvent selected from the group consisting of DMSO and ethanol.

Increasing Solubility

Some embodiments increase the solubility of curcumin in water byemploying a solid dispersion, such as those made with polyethyleneglycol 6000 (PEG 6000) or polyvinylpyrrolidone K-30 (PVP K30). Ruan, J.Pharm Biomed. Anal. 2005 Jul. 1; 38(3):457-64. Paradkar, Int. J. Pharm.2004 Mar. 1; 271(1-2):281-6

Some embodiments increase the solubility of curcumin in water byemploying inclusion complexes, such as those made with beta-cyclodextrin(BCD) and hydroxypropyl-beta-cyclodextrin (HPBCD). Ruan, J. PharmBiomed. Anal. 2005 Jul. 1; 38(3):457-64.

In some embodiments, the curcumin may be delivered in the form of acurcumin-PEG conjugate made in accordance with PCT Published PatentApplication WO2008051474 and U.S. Provisional Application No.60/862,057, filed Oct. 19, 2006, (collectively “Safavy”) thespecifications of which are incorporated by reference in theirentireties. Safavy reports that the water solubility of one of thesecurcumin-PEG conjugates is about 1.5 g/ml.

Other Curcumin Analogs

Modifications of curcumin and its functional fragments that eitherenhance or do not greatly affect the ability to treat AD are alsoincluded within the term “curcumin.” Such modifications include, forexample, additions, deletions or replacements of one or more functionalgroups. These modifications will either enhance or not significantlyalter the structure, conformation or functional activity of curcumin ora functional fragment thereof. Additionally, curcumin or its functionalfragments can be modified by the addition of epitope tags or othersequences that aid in its purification and which do not greatly affectits activity. As used herein, the term “functional fragment,” inconnection with an curcumin, is intended to mean any portion of curcuminthat maintains its to inhibit oxidation, or to prevent beta amyloidoligomer formation. If desired, a functional fragment can includeregions of the curcumin with activities that beneficially cooperate withthe ability to inhibit oxidation or oligomer formation.

Also in accordance with the present invention, publicly known analogs ofcurcumin may be used.

In some embodiments, the curcumin analogs are those found in USPublished patent application US 2006/0067998.

Curcumin is soluble in ethanol, alkalis, ketones, acetic acid andchloroform. It is insoluble in water. Curcumin is therefore lipophilic,and generally readily associates with lipids, e.g. many of those used inthe colloidal drug-delivery systems of the present invention. In certainembodiments, curcumin can also be formulated as a metal chelate.

As used herein, curcumin analogues are those compounds which due totheir structural similarity to curcumin, exhibit anti-proliferative orpro-apoptotic effects on cancer cells similar to that of curcumin.Curcumin analogues which may have anti-cancer effects similar tocurcumin include Ar-tumerone, methylcurcumin, demethoxy curcumin,bisdemethoxycurcumin, sodium curcuminate, dibenzoylmethane,acetylcurcumin, feruloyl methane, tetrahydrocurcumin,1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione (curcumin1),1,7-bis(piperonyl)-1,6-heptadiene-3,5-dione(piperonylcurcumin)1,7-bis(2-hydroxy naphthyl)-1,6-heptadiene-2,5-dione(2-hydroxylnaphthyl curcumin), 1,1-bis(phenyl)-1,3,8,10-undecatetraene-5,7-dione(cinnamyl curcumin) and the like (Araujo and Leon, 2001; Lin et al.,2001; John et al., 2002; see also Ishida et al., 2002). Curcuminanalogues may also include isomers of curcumin, such as the (Z,E) and(Z,Z) isomers of curcumin. In a related embodiment, curcumin metaboliteswhich have anti-cancer effects similar to curcumin can also be used inthe present invention. Known curcumin metabolites include glucoronidesof tetrahydrocurcumin and hexahydrocurcumin, and dihydroferulic acid. Incertain embodiments, curcumin analogues or metabolites can be formulatedas metal chelates, especially copper chelates. Other appropriatederivatives of curcumin, curcumin analogues and curcumin metabolitesappropriate for use in the present invention will be apparent to one ofskill in the art.

In some embodiments, the curcumin analogs are those found in USPublished patent application US 2005/0181036.

Commercial curcumin includes three major components: curcumin (77%),demethoxycurcumin (17%), and bisdemethoxycurcumin (3%), which are oftenreferred to as “curcuminoids.” As used herein, “curcumin” is defined toinclude any one or more of these three major components of commercialcurcumin, and any active derivative of these agents. This includesnatural and synthetic derivatives of curcumin and curcuminoids, andincludes any combination of more than one curcumenoid or derivative ofcurcumin. Derivatives of curcumin and curcumenoids include thosederivatives disclosed in U.S. Patent Application Publication20020019382, which is herein specifically incorporated by reference.

In some embodiments, the curcumin analogs are those found in USPublished patent application US 2005/0267221:

In certain aspects,1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadi-ene-3,5-dione is thecurcumin that may be used in the present invention. Other curcuminanalogues (curcuminoids) that may be used include, for example,demethoxycurcumin, bisdemethoxycurcumin, dihydrocurcumin,tetrahydrocurcumin, hexahydrocurcumin, dihydroxytetrahydrocurcumin,Yakuchinone A and Yakuchinone B, and their salts, oxidants, reductants,glycosides and esters thereof. Such analogues are described in U.S.Patent Application 20030147979; and U.S. Pat. No. 5,891,924 both ofwhich are incorporated in their entirety herein by reference.

Other curcumin analogues (curcuminoids) that may be used includedihydroxycurcumin and NDGA.

Further examples of curcumin analogues include but are not limited to(a) ferulic acid, (i.e., 4-hydroxy-3-methoxycinnamic acid;3,4-methylenedioxy cinnamic acid; and 3,4-dimethoxycinnamic acid); (b)aromatic ketones (i.e., 4-(4-hydroxy-3-methoxyphenyl)-3-buten-2-one;zingerone; 4-(3,4-methylenedioxyphenyly-2-butanone;4-(p-hydroxyphenyl)-3-buten-2-one; 4-hydroxyvalerophenone;4-hydroxybenzylactone; 4-hydroxybenzophenone;1,5-bis(4-dimethylaminophen-yl)-1,4-pentadien-3-one); (c) aromaticdiketones (i.e., 6-hydroxydibenzoylmethane) (d) caffeic acid compounds(i.e., 3,4-dihydroxycinnamic acid); (e) cinnamic acid; (f) aromaticcarboxylic acids (i.e., 3,4-dihydroxyhydrocinnainic acid;2-hydroxycinnamic acid; 3-hydroxycinnamic acid and 4-hydroxycinnamicacid); (g) aromatic ketocarboxylic acids (i.e., 4-hydroxyphenylpyruvicacid); and (h) aromatic alcohols (i.e., 4-hydroxyphenethyl alcohol).These analogues and other representative analogues that can be used inthe present invention are further described in WO9518606 and WO01040188,which are incorporated herein by reference in their entirety.

Curcumin or analogues thereof may be purified from plants or chemicallysynthesized using methods well known and used by those of skill in theart. Plant-derived curcumin and/or its analogues can be obtained byextraction from plants including Zingiberaceae Curcuma, such as Curcumalonga (turmeric), Curcuma aromatica (wild turmeric), Curcuma zedoaria(zedoary), Curcuma xanthorrhiza, mango ginger, Indonesian arrowroot,yellow zedoary, black zedoary and galangal. Methods for isolatingcurcuminoids from turmeric are well known in the art (Janaki and Bose,1967). Still further, curcumin may be obtained from commercial sources,for example, curcumin can be obtained from Sigma Chemicals Co (St.Louis, Mo.).

Any conventional method can be used to prepare curcumin and itsanalogues to be used in the present invention. For example,turmericoleoresin, a food additive, which essentially contains curcumin,can be produced by extracting from a dry product of rhizome of turmericwith ethanol at an elevated temperature, with hot oil and fat orpropylene glycol, or with hexane or acetone at from room temperature toa high temperature. Alternatively, those can be produced by the methodsdisclosed in Japanese Patent Applications 2000-236843, H-11-235192 andH-6-9479, and U.S. Patent Application No. 20030147979, which isincorporated by reference herein in its entirety.

In certain embodiments, a purified product of at least one curcuminand/or its analogue may be used. Alternatively, a semi-purified or crudeproduct thereof may be used, provided that it does not containimpurities which may not be acceptable as a pharmaceutical or foodproduct.

Preferred Analogues

There has been limited testing of the potency of curcumin analogsagainst beta amyloid. Park, J. Nat. Prod., 65, 9 Sep. 2002, reportstesting the following curcumin analogs for the ability to provide invitro protection for PC 12 cells against beta amyloid insult:

-   4″-(3′″-methoxy-4′″-hydroxyphenyl)-2″-oxo-3″-enebutanyl3-(3′-methoxy-4′    hydroxyphenyl) propenoate (31);-   1-(4-hydroxy-3-methoxyphenyl)-7-(4-hydroxyphenyl)-1,6-heptadiene-3,5-dione    (demethoxycurcumin)(32);-   1,7-bis(4-hydroxyphenyl)-1,6-heptadiene-3,5-dione    (bisdemethoxycurcumin), (33); and-   1,7-bis(4-hydroxyphenyl)-1-heptene-3,5-dione (34).    Each of these compounds is shown in FIG. 1 d. Park reports the    following results, as shown in Table IV:

TABLE IV anti-βA (25-35) anti-βA (1-42) Analog ED50^(a) (μg/ml) ED50(μg/ml) curcumin 7.0 +/− 1.1 10.0 +/− 0.9  31 1.0 +/− 0.3 2.0 +/− 0.4 324.0 +/− 0.5 5.0 +/− 0.5 33 2.0 +/− 0.6 3.5 +/− 0.7 34 0.5 +/− 0.2 1.0+/− 0.3 ^(a)ED50 represents the sample concentration that is required toachieve 50% cell viability.^(a) ED50 represents the sample concentration that is required toachieve 50% cell viability.

Analysis of the Park data reveals that each of compounds (31)-(34) is amore potent neuroprotectant against beta amyloid than curcumin, withcompounds (31) and (34) being on the order of 5 and 10 fold more potent.Therefore, in preferred embodiments, each of compounds (31)-(34) is usedby itself or in combination as the parent compound for the manufacturingand use of a curcumin prodrug. Each of the parent compounds may beobtained by the methods disclosed in Park.

Kim, Neuroscience Lett. 303 (2001) 57-61 similarly reports testing thefollowing curcumin analogs for the ability to provide in vitroprotection for PC 12 cells against beta amyloid insult as shown in TableV:

TABLE V anti-BA (25-35) anti-BA (1-42) Analog ED50 (μg/ml) ED50 (μg/ml)Curcumin 7.1 +/− 0.3 6.8 +/− 0.4 Demethoxycurcumin 4.7 +/− 0.1 4.2 +/−0.3 Bisdemethoxycurcumin 3.5 +/− 0.2 3.0 +/− 0.3Analysis of the Kim data reveals that each of the demethoxycurcumin andbisdemethoxycurcumin compounds is a more potent neuroprotectant againstbeta amyloid than curcumin, with the demethoxycurcumin andbisdemethoxycurcumin compounds being on the order of 1.5 and 2 fold morepotent. This data is in substantial agreement with the relativepotencies of demethoxycurcumin and bisdemethoxycurcumin reported by Parkabove.

From Chen, Free Rad. Biol. Med., 2006 Feb. 1; 40(3):526-35, thecompounds hydroxycurcumin and dihydroxycurcumin can be obtained bydemethylation of curcumin with AlCl₃-pyridine as described in Mazumder,“Curcumin analogs with altered potencies against HIV-1 integrase asprobes for biochemical mechanism of drug action, J. Med. Chem. 40(1997), pp. 3057-3063.

Phenyl ring-substituted analogues of curcumin can be synthesized bycondensation of 2,4-pentanedione with two equivalents of the substitutedbenzaldehyde based on the available methods, such as those described inMazumder, “Curcumin analogs with altered potencies against HIV-1integrase as probes for biochemical mechanism of drug action”, J. Med.Chem. 40 (1997), pp. 3057-3063; U.S. Pat. No. 6,900,356 (Gokaraju), thespecification of which is incorporated by reference in its entirety; andRoughley, “Experiments in biosynthesis of curcumin”, J. Chem. Soc.Perkin Trans. 1 (1973), pp. 2379-2388.

Generally, as described in Chen, Free Rad. Biol. Med., 2006 Feb. 1;40(3):526-35, 2,4-pentanedione (1.0 g, 0.01 mol) and boron oxide (0.49g, 0.007 mol) can be dissolved in EtOAc (10 ml) and stirred for 0.5 h at40° C. followed by addition of the corresponding benzaldehyde (0.02 mol)and tributyl borate (4.6 g, 0.02 mol) and stirred for additional 0.5 h.Then n-butylamine (1 ml) in EtOAc (10 ml) can be added dropwise during30 min. After further stirring for 4 h at 40° C. the mixture can beallowed to stand overnight to complete the reaction. The mixture canthen be hydrolyzed by HCl (0.4 N, 15 ml) and the aqueous layer can beextracted three times with EtOAc. The combined organic layers can bewashed with water and dried over Na₂SO₄. After removal of the solventunder reduced pressure the residual paste can be purified by columnchromatography (silica gel, cyclohexane-EtOAc) and recrystallized fromEtOH to give pure curcumin analogs.Other Diseases

In other embodiments, the present invention relates to the intranasaladministration of a formulation comprising an effective amount ofcurcumin across the cribriform plate and into the brain in order totreat a stroke.

In other embodiments, the present invention relates to the intranasaladministration of a formulation comprising an effective amount ofcurcumin across the cribriform plate and into the brain in order totreat multiple sclerosis.

Other Polyphenolic Prodrugs

In some embodiments, the curcumin is combined with a second lipophilictherapeutic agent, preferably another polyphenol, such as resveratrol.In some embodiments, the curcumin is provided in a formulation withanother compound selected from the group consisting of gingko bilobaextract, resveratrol, and a green tea catechin, and then is intranasallyadministered.

Also in accordance with the present invention, there is provided amethod for transporting a gingko biloba extract to a brain of a mammal,comprising:

a) applying a pharmaceutical composition comprising a gingko bilobaextract to an upper third of a nasal cavity of the mammal, wherein thegingko biloba extract is absorbed through an olfactory mucosa andtransported to the brain of the mammal.

Also in accordance with the present invention, there is provided amethod for transporting resveratrol to a brain of a mammal, comprising:

a) applying a pharmaceutical composition comprising resveratrol to anupper third of a nasal cavity of the mammal, wherein the resveratrol isabsorbed through an olfactory mucosa and transported to the brain of themammal.

Also in accordance with the present invention, there is provided amethod for transporting a green tea catechin to a brain of a mammal,comprising:

a) applying a pharmaceutical composition comprising the catechin to anupper third of a nasal cavity of the mammal, wherein the catechin isabsorbed through an olfactory mucosa and transported to the brain of themammal.

The prodrug rationale provided above for curcumin can also be applied toother therapeutic phenolic compounds (preferably, therapeuticpolyphenolic compounds), such as those of the flavonoid class. Inpreferred embodiments, this compound is selected from the groupconsisting of resveratrol, hispidin, genistein, ellagic acid, 1,25dihydroxyvitamin D3, the green tea catechin EGCG, and docosahexaenoicacid (DHA). In another embodiment, this compound is docosahexaenoic acid(DHA). Also in accordance with the present invention, there is provideda method for transporting a flavonoid prodrug to a brain of a mammal,comprising:

a) applying a pharmaceutical composition comprising a flavonoid prodrug(such as a resveratrol prodrug) to an upper third of a nasal cavity ofthe mammal, wherein the flavonoid prodrug is absorbed through anolfactory mucosa and transported to the brain of the mammal.Resveratrol

In especially preferred embodiments, the flavonoid prodrug isresveratrol.

Resveratrol, a polyphenolic compound commonly found in red wine, hasbeen promoted as a possible treatment for Alzheimer's Disease because itappears to affect multiple mechanisms of AD pathology. Anekonda, BrainResearch Reviews, 52, 2006, 316-26.

First, resveratrol has been shown to reduce the amount of beta amyloidin brain tissue. The mechanism by which resveratrol accomplishes thishas been subject to debate. One recent paper concludes that resveratrolis a specific inhibitor of BACE1 enzyme, with an IC₅₀ of about 15 uM.Jeon, Phyomedicine, 2006 Nov. 2 (E-pub). Another recent paper reportsthat resveratrol reduces beta amyloid content by promoting intracellulardegradation of beta amyloid via a mechanism that involves theproteosome. Marambaud, J. Biol. Chem., 280(45), 37377-82.

Second, it is believed that resveratrol inhibits the formation of betaamyloid fibrils. Riviere, Bioorg. Med. Chem., 2006 Oct. 1 (E-pub).

Third, 20 μM resveratrol has a neuroprotective effect against betaamyloid-induced neurotoxicity in rat hippocampal neurons, and isbelieved to provide this neuroprotection through activation of proteinkinase C(PKC). Han, Br. J. Pharmacology, 2004, 141, 997-1005. Han, J.Pharmacol. Exp. Ther., 2006 July 318(1)238-45 (Epub 2006 Mar. 30),reports the existence of specific plasma membrane binding sites forresveratrol in the rat brain (Ki=102 nM), and notes that the potency ofresveratrol analogs in protecting rat hippocampal cells against betaamyloid-induced neurotoxicity correlates well with their apparentaffinity.

The hypothesis that resveratrol acts through PKC is of special interestbecause it is believed that nonamyloidogenic processing of amyloidprecursor protein (APP) also acts through activation of PKC.

Fourth, some hypotheses of Alzheimer's Disease involve oxidation viaenhanced brain concentrations of heavy metals. Respecting resveratrol,it has been reported that resveratrol is a highly potent chelator ofcopper. Belguendouz, Biochemical Pharmacology, 53, 1347-1355, 1997.

Fifth, Anekonda, Brain Research Reviews, 52, 2006, 316-26 reports thatmechanisms of aging and AD are intricately linked and that thesemechanisms can be modulated by both calorie restriction regimens andcalories restriction mimetics, the prime mediator of which is the SIRT1protein. Howitz, Nature, 2003, 425, 191-196 reports that resveratrol hasbeen found to exhibit the highest level of SIRT1 activation amongst thesmall molecules tested. Chen, J. Biol. Chem., 280, 48, 40364-74 foundthat resveratrol markedly reduced NF-KB signaling in microglia, andascribed this benefit to the induction of SIRT1 by resveratrol.Similarly, Kim, Int. J. Mol. Med., 2006 Jun. 17, 6, 1069-75 reports thatmodulation of NF-KB activity is involved in the neuroprotective actionof resveratrol against beta amyloid induced neurotoxicity.

Sixth, resveratrol is a well known anti-oxidant, and 5-25 uM resveratrolhas displayed an ability to protect cultured hippocampal cells againstnitric oxide related neurotoxicity. Bastianetto, Br. J. Pharm., 2000,131, 711-720. Similarly, Savaskan, Gerontology, 2003 November-December,49(6) 380-3 reports that resveratrol maintains cell viability againstbeta amyloid-related oxidative stress, and exerts its antioxidativeaction by enhancing the intracellular free radical scavengerglutathione.

The bioavailability of resveratrol has been well studied. Sinceresveratrol appears to be highly susceptible to glucuronidation in theintestine and liver, it has been concluded that the oral bioavailabilityof resveratrol is “about zero”. Wenzel, Mol. Nutr. Food Res., 2005, 49,472-481. Accordingly, because of the finding that trans-resveratrol inpresent in human serum in its glucuronide form rather than in its freeform, Vitaglione, Mol. Nutr. Food Res., 2005 May 49(5), 495-504, raisessome doubts about the heath effect of dietary consumption ofresveratrol. Thus, the intranasal rationale for trans-resveratrolappears warranted.

Nonetheless, it appears that when resveratrol reaches the brain, it hasa fairly significant residence time. El-Mohsen, British J. Nutrition,2006, 96, 62-70, reports that the resveratrol concentration in the brainabout 18 hours after gastric administration was still 43% of thatmeasured at 2 hours. Wang, Brain Research, 958 (2002), 439-447, reportsthat intraperitoneal administration of resveratrol provides a peakconcentration in the brain 4 hours after its administration.

Trans-resveratrol has a molecular weight of about 228, and is verylipophilic (having an octanol-water partition coefficient Log P of about3.14). However, its solubility in water is very low (<0.01 mol/L). Thus,the prodrug rationale for trans-resveratrol appears warranted.

Hybrids

This section discloses other curcuminoid drugs of the present inventionthat represent hybrids between curcumin and other polyphenols.

FIGS. 2-16 disclose various curcumin derivatives that are hybrids ofcurcumin and various other natural polyphenols. Each of thesederivatives is a triphenolic compound, wherein the intermediate diketonestructure of curcumin is replaced with a phenolic group. The resultingcompound retains the spacing between the two phenols of curcumin, andalso possesses the biphenolic spacing of the additional polyphenol.FIG. 2 discloses the structures of curcumin, resveratrol, and twocurcumin-resveratrol hybrids. Note how each of the hybrids retains theinterphenolic spacing of each of curcumin and reveratrol.FIG. 3 discloses a method of making the curcumin-resveratrol I hybrid.FIG. 4 discloses a method of making the curcumin-resveratrol II hybrid.FIG. 5 discloses a method of making a curcumin-resveratrol hybrid havingthree hydroxyl groups in each of the central phenolic group and lateralphenolic groups.FIG. 6 discloses curcumin, resveratrol and a hybrid thereof, wherein allof the phenolics of the natural compounds are represented in the hybrid,providing trihydroxyl lateral phenolic groups and a dihydroxyl centralphenolic group.FIG. 7 discloses a method of making the curcumin-resveratrol hybrid ofFIG. 6.FIG. 8 is similar to the hybrid of FIG. 6, but wherein the methoxygroups of the base curcumin molecule are retained.FIG. 9 discloses curcumin, oxyresveratrol and a hybrid thereof, whereinall of the hydroxyls/phenolics of the natural compounds are representedin the hybrid, providing trihydroxyl lateral phenolic groups and atrihydroxyl central phenolic group.FIG. 10 discloses curcumin, piceatannol and a hybrid thereof, whereinall of the hydroxyls/phenolics of the natural compounds are representedin the hybrid, providing trihydroxyl lateral phenolic groups and atrihydroxyl central phenolic group.FIG. 11 discloses a method of making a curcumin-resveratrol hybrid,wherein all of the hydroxyls/phenolics of the natural compounds arerepresented in the hybrid, providing trihydroxyl lateral phenolic groupsand a dihydroxyl central phenolic group.FIG. 12 discloses curcumin, BDMC, resveratrol and curcumin hybridsthereof, wherein all of the phenolics of the natural compounds arerepresented in the hybrid, providing hydroxyl demethoxy lateral phenolicgroups and a hydroxy or dihydroxyl central phenolic group.

Narlawar, Neurodegen. Dis., 2007, 4(2-3) 88-93, reports that certainoxazole and pyrazole analogs of curcumin act as inhibitors ofgamma-secretase in the low micromolar range. Of interest, it has beenreported that these oxazole and pyrazole analogs have substantially thesame anti-oxidant activity as natural curcumin. Selvam, Bioorg. & Medic.Chem. Letters 15 (2005) 1793-1797. Therefore, these molecules may bevery valuable as therapeutic agents for Alzheimer's Disease. Thegeneralized feature of these oxazole and pyrazole analogs of curcumin isthat they replace the 2,4 diketone entity of natural curcumin with acyclic N-containing heterocycle. This cyclic entity is believed toreduce the rotational freedom of the molecule.

Another such molecule that possesses a cyclic entity in the place of the2,4 diketone entity is shown in FIG. 12. There are at least four reasonsfor believing that the FIG. 12 curcuminoid will have superiorperformance (as compared to natural curcumin) against Alzheimer'sDisease:

First, elimination of the original methoxy substituents of thecurcuminoid means that this curcuminoid will behave more like BDMC,shown in (33) above. As reported above by Park and Chen, BDMC is abouttwice as potent as natural curcumin in surviving toxic insult by βamyloid. Therefore, this FIG. 12 curcuminoid should be about twice aspotent as natural curcumin in surviving toxic insult by β amyloid.

Second, the BDMC-like nature of the FIG. 12 curcuminoid should correctdefects in the innate immune response of peripheral macrophages of theAD patient, as reported by Fiala, Proc Natl Acad Sci U S A. 2007 Jul.31; 104(31):12849-54. According to Fiala, activated peripheralmacrophages of the innate immune response are thought to be responsiblefor the beneficial clearance of amyloid plaques in the brain. However,in many AD patients, these macrophages possess defects in internalizingβ-amyloid which render them unable to clear deposited amyloid plaques,and so plaques build up in the brain and cause microglia-inducedneuroinflammation. The resulting inflammation then upregulates β amyloidproduction, thereby provoking a vicious cycle. Fiala reports that BDMCis the curcuminoid responsible for correcting this defect in peripheralmacrophages, and works optimally at a concentration of 0.1 uM.

Third, the center cyclic entity of the FIG. 12 curcuminoid is believedto reduce the rotational freedom of the molecule, thereby locking in aconformation in which the hydroxyls of the outer phenyl groups are farapart from each other. As the structural similarity between curcumin andCongo red has been reported to be the reason for the potent amyloidbinding of each molecule, it appears that the conformation of curcuminthat is the most potent amyloid binder is that in which the hydroxyls ofthe outer phenyl groups are far apart from each other. Therefore, FIG.12 curcuminoid should have amyloid binding qualities that are superiorto natural curcumin.

Fourth, inspection of this molecule reveals that it possesses virtuallyall of the structural characteristics of resveratrol in general, asshown in FIG. 12. Therefore, it is believed that this FIG. 12 moleculewill possess the therapeutic qualities of both curcumin and resveratrol.Micromolar amounts of resveratrol significantly upregulates sirtuinexpression Howtiz, Nature. 2003 Sep. 11; 425(6954):191-6, and sirtuinshave been known to increase the alpha-amyloidogenic pathway of amyloidprocessing. Qin, J Biol. Chem. 2006 Aug. 4; 281(31):21745-54. This isadvantageous because it is believed that production of the neurotoxicβ-amyloid protein occurs through the β-amyloid pathway.

Therefore, it is believed this molecule of FIG. 12 will not only possessall the benefits of traditional curcumin, it will also possess:

i) better survival (due to BDMC features)

ii) better macrophage activation (due to BDMC)

iii) better binding to amyloid (reduced rotational freedom)

iv) non-amyloidogenic processing (due to resveratrol-induced sirtuinexpression).

Of note, Narlawar, Neurodegen. Dis., 2007, 4(2-3) 88-93, expects that,due to their reduced rotational freedom, the oxazole and pyrazoleanalogs of curcumin would not possess the metal chelation abilities ofnatural curcumin. While it may be that the oxazole and pyrazole analogsof curcumin may not possess the chelation abilities of natural curcumin,it is expected that the FIG. 12 molecule would retain the chelationabilities of resveratrol. Because resveratrol is a potent chelator, itis expected that the FIG. 12 molecule would possess potent chelationabilities.

FIG. 13 provides a method of making the compound of FIG. 12 that hashydroxyl demethoxy lateral phenolic groups and a hydroxy centralphenolic group.

FIG. 14 provides a method of making the compound of FIG. 12 that hashydroxyl demethoxy lateral phenolic groups and a dihydroxy centralphenolic group.

FIG. 15 discloses curcumin, piceatannol and a hybrid thereof, whereinmost of the hydroxyls of the natural compounds are represented in thehybrid, providing dihydroxyls in the end phenolic groups and a singlehydroxyl in the central phenolic group in the positions common with thetwo natural compounds. Kim, Ann N Y Mad Sci., 2007 January; 1095:473-82reports that piceatannol treatment attenuates the intracellularaccumulation of ROS induced by treatment of PC12 cells with Aβ, andinhibited Aβ-induced apoptotic features including internucleosomal DNAfragmentation, nucleus condensation, cleavage ofpoly(ADP-ribose)polymerase (PARP), and activation of caspase-3.FIG. 16 provides a method of making the compound of FIG. 15.FIG. 17 discloses the structures of curcumin, 3,3′,4′ fisetin and acurcumin-3,3′,4′ fisetin hybrid, wherein all of the hydroxyls of thecurcumin and 3,3′,4′ fisetin compounds are represented in the hybrid,providing dihydroxyls in the end phenolic groups and a hydroxyl in theplace of each double bond. Maher, Free Radic Res. 2006 October;40(10):1105-11 reports that fisetins in general and 3,3′,4′ fisetin inparticular have potent (low micromolar) neurotrophic properties.FIG. 18 discloses a method of making the curcumin-3,3′,4′ fisetin hybridof FIG. 17.FIG. 19 discloses the structures of curcumin, honokiol and acurcumin-honokiol hybrid, wherein all of the hydroxyls of the curcuminand honokiol compounds are represented in the hybrid, providing a singlehydroxyl in the end phenolic groups and a hydroxyl in the place of eachdouble bond. Fukuyama, Bioorg Med Chem. Lett. 2002 Apr. 22; 12(8):1163-6reports that honokiol has potent neurotrophic properties.FIG. 20 discloses a method of making the curcumin-honokiol hybrid ofFIG. 19.FIG. 21 discloses a method of making a FIG. 13—honokiol hybrid, whereinall of the hydroxyls of the natural compounds are represented in thehybrid, providing single hydroxyl in the end phenolic groups in thepositions common with the two natural compounds, a hydroxyl in thecentral phenolic group, and a hydroxyl in the place of each curcumindouble bond.FIG. 22 discloses a method of making a FIG. 15—3,3′,4′ fisetin hybrid,wherein all of the phenolics of the natural compounds are represented inthe hybrid, providing single hydroxyl in the end phenolic groups and ahydroxy central phenolic group in the positions common with the twonatural compounds, and an additional hydroxyl in the place of eachcurcumin double bond.Transdermal Iontophoresis

In some embodiments, the curcuminoid drug is delivered to thebloodstream of the patient via transdermal iontophoresis. Iontophoresisrefers to the introduction, by means of an electric current, of ions ofsoluble salts into the tissues of the body. In iontophoretic deliverysystems, an applied electric potential gradient is employed to enhancethe transdermal delivery of ionized drug molecules.

In a preferred embodiment, a charged curcuminoid prodrug is administeredtransdermally by iontophoresis. Preferably, the ionized or ionizabledrug molecule is preferably a charged curcumin glycinate ester, whichexhibits enhanced iontophoretic transdermal flux over that of theunmodified parent compound.

The literature reports the transdermal iontophoresis of ionicallycharged prodrugs. In particular, Laneri, Pharm. Res., 16, 12, 1999,1818-1824 investigated the benefits of iontophoretically transporting aprodrug of DHEA, which is a lipophilic polycyclic alcohol like curcumin.Laneri reports the iontophoretic flux of PRO2 (an ionic prodrug of DHEAhaving a trimethylglycinate prodrug moiety) as being 0.0714 μmol cm⁻²h⁻¹, or about 20 μg/(cm²·h). Likewise, U.S. Pat. No. 5,622,944 (ALZA)reports the iontophoretically transporting an ionic prodrug oftestosterone, which is a lipophilic polycyclic alcohol like curcumin.U.S. Pat. No. 5,622,944 reports an iontophoretic flux oftestosterone-17β-stachydrine ester, chloride salt (testosterone having ahetereocyclic amine prodrug moiety) as being about 40 μg/(cm²·h). Ineach case, the investigator found a virtual absence of the prodrug inthe receiving reservoir, indicating that the skin-based esterasescleaved the ester moiety of the prodrug, thereby allowing the base drugto enter the receiving reservoir. Accordingly, it is believed thatskin-based esterases will cleave the ester moiety of the curcuminprodrug, thereby allowing the base curcumin drug to enter the receivingblood stream.

Therefore, it is believed that curcumin may be safely delivered into theblood stream in pharmaceutically significant quantities by thetransdermal iontophoresis of ionically charged curcumin prodrugs oranalogs.

The predicted concentration of a drug delivered through transdermaliontophoresis can be found via the equation:

${Concentration} = {\frac{{Flux} \times {Surface}\mspace{14mu}{Area}}{Clearance} = \frac{J \times {SA}}{Cl}}$where

Concentration is provided in (μg/l),

Flux is provided in μg/(cm²·h),

Surface Area is provided in (cm²), and

Clearance is provided in (l/hr).

In general, the literature has reported the transdermal iontophoresis ofcharged small molecules produces fluxes in the following approximateranges provided in Table VI:

TABLE VI Reservoir Reservoir Flux Drug Conc. (mM) Volume (ml) μg/(cm² ·h) Source Testosterone  4 mg/ml 1 ml 40 a DHEA (PRO2) 0.85 mg/ml   1 20b Salicylic Acid  2 mg/ml 0.5 41.17 c. SNA 0.2 mg/ml  8 ml 23.02 d.5-OH-DPAT 2.3 mg/ml  NA 90 e Timolol 10 mg/ml 2 ml 200 f Timolol 20mg/ml 2 ml 250 f Atenolol 40 mg/ml 2 ml 400 f a U.S. Pat. No. 5,622,944(ALZA) (reported as 4 mM) b Laneri, Pharm. Res., 16, 12, 1999, 1818-1824c. Murthy, J Pharm Sci. 2007 Feb; 96(2): 305-11 d. Fang, Int J Pharm.2002 Mar 20; 235(1-2): 95-105 e Nugroho, J. Controlled Release, 103, 2,21 March 2005, 393-403 f Denet, Pharm Res. 2003 Dec; 20(12): 1946-51.As demonstrated above, it is reasonable to conclude that glycinate-basedcurcumin prodrugs can achieve aqueous solubilities in the range of 25-50mg/ml, which is far above the range of drug concentrations used in theupper portion of the above Table. Therefore, it is very reasonable toconclude that transdermal iontophoresis of charged curcumin can, in aworst case, produce fluxes at least similar to those reported in theupper portion of Table VI, that is, in the range of about 35 μg/(cm²·h).

In general, the literature has reported that electrodes associated withthe transdermal iontophoresis of charged small molecules are found inthe following size ranges in Table VII:

TABLE VII Range of Preferred Surface Areas Surface Area Drug (cm²) (cm²)Source Testosterone 5-50 25 a DHEA 50 50 b a U.S. Pat. No. 5,622,944(ALZA) b Laneri, Pharm. Res., 16, 12, 1999, 1818-18-24Therefore, it is reasonable to conclude that transdermal iontophoresisof charged curcumin can be accomplished with electrodes having a 50 cm²surface area (about a three inch square).

Vareed, Cancer Epidiol. Biomarkers Prev., 2008 June; 17(6) 1441-7reported on the pharmacokinetics of curcumin conjugate metabolites inhealthy human volunteers, and found that for a dose (D) of about 11 g,the area-under-the-curve (AUC) was estimated to be about 30 μg/ml·hr.However, such values appear to relate to conjugated curcumin, not freecurcumin. Nonetheless, the data from Vareed are useful because it isbelieved that the transdermal transfer of curcumin will avoid theprecise metabolism by the gut and liver that caused Vareed to findsubstantially conjugated curcumin in their human subjects and not freecurcumin.

Therefore, since Clearance (Cl) is found by:Cl=D/AUC,we can reasonably estimate the clearance (Cl) of curcumin in humans asbeing about 11 g/(30 μg/ml·hr), or about 350 L/hr. A clearance value ofCl=350 L/hr is substantially equivalent to the 495 L/hr and 713 L/hrvalues reported by Shoba, Planta Med. 1998 May; 64(4):353-6 in the oraldosing of rats with either curcumin alone or curcumin with piperine.

Therefore, the following analysis will use a clearance value of 350L/hr. It is likely that the 350 L/hr value is a conservative estimatefor iontophoresis in that it reflects the significant amount ofmetabolism that occurs during oral dosing of curcumin which would beabsent in the dermal transfer setting. Rather, it is likely that theclearance value of 7.33 L/hr reported by Shoba for the oral dosing ofcurcumin plus piperine would be more predictive in the iontophoresissetting because piperine disables the drug enzymes systems of the gutand liver and so provides a transfer substantially absent of metabolicinterference, as is anticipated for iontophoresis. Nonetheless, thefollowing analysis will use a clearance value of 350 L/hr.

Now that each of flux, surface area and clearance values have beenprovided, the predicted plasma concentration of curcumin reasonablyachievable by transdermal iontophoresis can be calculated:

$\begin{matrix}{{{Concen}.} = \frac{{Flux} \times {Surface}\mspace{14mu}{Area}}{Clearance}} \\{= \frac{J \times {SA}}{Cl}} \\{= \frac{35 \times 50}{350}} \\{= {{5\mspace{14mu}{\mu g}\text{/}I} \sim {0.012\mspace{14mu}{{µM}.}}}}\end{matrix}$

Thus, a worst case plasma concentration of curcumin achievable bytransdermal iontophoresis can be predicted as 0.012 μM, or about 5ng/ml.

Since curcumin crosses the blood brain barrier fairly easily, it isbelieved that curcumin will achieve at least substantially the sameconcentration in the brain as the blood. This assumption is supported bythe curcumin literature. For example, Yang. J. Biol. Chem., 280(7),5892-5901 (2005) reports that mouse brain curcumin levels of about 1.1μM were measured one hour after dosing that produced a 1.6 μMconcentration in the plasma. Likewise, Begum, J. Pharmacol Exp Ther.2008 Apr. 16. reports that, for i.p. and i.m. administration of curcuminin mice, the curcumin concentration is about 5 fold higher in brain thanin plasma. Therefore, it is reasonable to conclude that theiontophoresis of curcumin prodrugs or analogs that can produce 0.012 μMplasma levels will also produce brain levels of at least about 0.012 μM.Thus, the AD patient may expect to gain valuable benefits fromiontophoretic transfer.

Therefore, in some embodiments, there is provided a method of deliveringa curcuminoid to a patient (preferably, an AD patient), comprising thesteps of:

-   -   a) iontophoretically delivering a charged curcuminoid        (preferably, a charged curcuminoid prodrug) across a skin of the        patient.

Although it has been predicted that transdermal iontophoresis canproduce a 0.012 μM plasma concentration in Alzheimer's patient, it isbelieved that simple modifications can lead to substantial increases inthe resultant plasma and brain concentrations. These involve changes tothe valence of the ionic prodrug, the magnitude of the iontophoresiscurrent, and the drug reservoir concentration. Each of these will now bedescribed below:

In general, increasing the concentration of drug in the iontophoreticreservoir leads to a linear increase in the drug's flux. For example,increasing the concentration of 5-OH-DPAT from 0.25 to 0.5, 1.3 and 2.3mg/ml resulted in a linear increase in flux from 39.1 to 78.4, 187.6 and318.2 nmol/(cm·h), respectively. Nugroho, J. Controlled Release, 103, 2,21 Mar. 2005, 393-403. As demonstrated above, it is reasonable toconclude that glycinate-based curcumin prodrugs can achieve aqueoussolubilities in the range of 25-50 mg/ml. This higher range is about10-fold greater the reservoir concentrations of the drugs reported inthe upper portion of Table VI. Therefore, it is reasonable to believethat the reservoir concentration of curcumin prodrug used to produce theiontophoresis can be increased to about 25-50 mg/ml, and the resultantflux and plasma concentration of curcumin can be respectively increasedto about 400 μg/(cm²·h) and about 60 ng/ml, or about 0.14 μM. Thus, abrain curcumin concentration of about 0.14 μM may be realized byiontophoresis.

Comparison of this 0.14 μM plasma value with the reported activity ofcurcumin in plasma reveals that the AD patient may expect to gainvaluable benefits from iontophoretic transfer. For example, Fiala, ProcNatl Acad. Sci. USA. 2007 Jul. 31; 104(31):12849-54 reports that 0.1 uMis the optimum level of BDMC that stimulates AD patients' macrophages toclear β amyloid. Thus, the 0.14 μM plasma concentration slightly exceedsthe 0.1 μM optimum level of BDMC reported by Fiala to stimulate ADpatients' macrophages to clear β amyloid.

The 60 ng/ml estimate of curcumin plasma concentration is also in linewith some iontophoresis-driven drug plasma values reported in the art.Indeed, the literature has reported that transdermal iontophoresis ofcharged molecules can produce serum concentrations that approach the 0.5μM range (˜200 ng/ml). For example, Bender, Arzneimittelforschung. 2001;51(6):489-92 reports that iontophoresis of 100 mg of etofenamate for 20minutes in humans produces a serum concentration of about 200 ng/ml.Conjeevaram Pharm Res. 2003 September; 20(9):1496-501 reports thationtophoresis via a 10 mg/ml patch of propranolol in rats with a 0.1mA/cm² current density produces a Cmax serum concentration of about 200ng/ml.

Abla, Pharm. Res, 2005 December; 22(12):2069-78, reports that highervalence ions display greater iontophoretic flux. Because higher valencemolecules are more easily transported by iontophoresis, it isadvantageous to replace not just one but both of the hydroxy groups ofthe curcumin molecule with charged glycinate moieties.

Therefore, in some embodiments, there is provided curcumin analogs(1′)-(30′) particularly suited for iontophoretic delivery, wherein eachof the hydroxyl groups of the curcumin base molecule is replaced withpolar or charged moieties (i.e., each of the two OH groups of the parentcurcumin molecule is replaced with an OR group). In embodiments used iniontophoresis, each of the hydroxyl groups of the parent curcuminmolecule is replaced with charged moieties, preferably ammoniumglycinate. In some embodiments, each of the hydroxyl groups of thecurcumin molecule are replaced with a trimethylglycinate moiety to makecurcumin di(trimethylglycinate)dichloride.

Therefore, solely through the use of a divalent curcumin salt, it isreasonable to believe that the resultant flux and plasma concentrationof curcumin can be respectively doubled to about 800 μg/(cm²·h) andabout 0.3 μM.

U.S. Pat. No. 5,622,944 reports that, in iontophoretic administration,the drug or prodrug delivery rate is proportional to the amount ofcurrent applied. The literature has reported that doubling the amperageof the current used to produce the iontophoresis can lead to a doublingof the drug flux. Since it is reasonable to believe that the currentused to produce the iontophoresis can be increased to about 0.5 mA/cm²,and the resultant flux and plasma concentration of curcumin can berespectively increased to about 800 μg/(cm²·h) and 0.3 μM.

Curcumin is highly lipophilic and therefore would be expected tobioaccumulate in fatty tissues such as brain tissue. Accordingly, it isreasonable to expect the curcumin concentration in a patient's brain tobe higher than the curcumin concentration in that patient's plasma. Asreported above, Yang. J. Biol. Chem., 280(7), 5892-5901 (2005) reportsthat mouse brain curcumin levels (1.1 μM) were about the same as itsplasma levels (1.6 μM) when measured one hour after dosing, while Begum,J. Pharmacol Exp Ther. 2008 Apr. 16. reports that, for i.p. and i.m.administration of curcumin in mice, the curcumin concentration in miceis about 5-13 fold higher in brain than in plasma. Without wishing to betied to a theory, it is believed that the numbers reported by Begumwould be more reflective of bioaccumulation, particularly Begum'schronic dosing, which produced brain/plasma ratios of between 3:1 and13:1. Therefore, if an 8-fold bioaccumulation factor is taken intoaccount, it is reasonable to conclude that the iontophoresis of curcuminprodrugs or analogs that can produce:

-   -   a) 0.012 μM plasma curcumin levels will also produce brain        levels of about 0.1 μM (assuming a worst case prodrug solubility        of about 2-5 mg/ml), and    -   b) 0.14 μM plasma curcumin levels will also produce a brain        curcumin concentration of about 1.1 μM (assuming a prodrug        solubility of about 25-50 mg/ml).

As explained above, the iontophoretic delivery of curcumin will provide,in a worst case, a serum/plasma concentration of about 0.012 μM (5μg/l), and may likely be able to achieve a serum/plasma concentration ofabout 0.3 μM (150 μg/l). These values are essentially equivalent to the0.006 μg/ml and 0.18 μg/ml serum Cmax values for oral curcumin reportedby Shoba, Planta. Med. 1998 May; 64(4):353-6, who provided volunteerswith 2 g/day of oral curcumin supplemented with piperine. Therefore, onthe basis of Cmax values alone, iontophoresis may be considered to besubstantially equivalent to oral dosing.

Moreover, iontophoretic delivery appears to be superior to oralcurcumin-piperine in two major respects. The first major advantage ofdelivering curcumin iontophoretically is that the iontophoretic deliveryinto the blood stream occurs not via a bolus, but rather occurs steadily24 hours a day. In contrast, oral delivery of curcumin as per Shobaoften produces a spiked delivery lasting less than about an hour in thebloodstream. Therefore, iontophoresis may provide a 24-fold advantageover oral delivery in terms of area-under-the-curve (AUC)bioavailability. Indeed, the 24 hour AUCs can be compared in Table VIII:

TABLE VIII Investigator Technology AUC (hr · ug/l) Present inventionIontophoresis worst case  5 ug/l × 24 = 120 likely 150 ug/l × 24 = 3600Vareed Oral Dosing ~30 Shoba Oral Dosing 4 Shoba Oral + piperine 80

Therefore, on the basis of AUC values alone, curcumin iontophoresis maybe considered to be substantially superior to oral curcumin dosing.

The second major advantage of iontophoresis over oral dosing withpiperine lies in the fact that piperine is a non-specific inhibitor ofmetabolic enzyme systems in the digestive tract and liver. Accordingly,patients taking other pharmaceuticals in addition to a curcumin-piperinetablet may find that, due to piperine disabling their native enzymesystems, all of the other pharmaceuticals they have ingested are alsobecoming much more bioavailable and therefore much more potent. Thus,iontophoretic curcumin may be much safer than oral dosing of curcuminplus piperine.

Therefore, iontophoretic curcumin may be able to deliver a much greateramount of curcumin than that reported by Shoba, but without disablingthe delicate drug-metabolizing enzyme systems in the gut and liver ofthe patient.

According to US Published Patent Application 2003/157155, transdermalformulations are preferably used for administration of activeingredients which, because of their physicochemical properties, areeasily able to overcome the barrier of the skin. To do this, the activeingredients must have sufficient solubility both in the lipophilicstratum corneum and in the underlying hydrophilic living epidermis.Flynn G., Stewart B. Drug Dev. Res. 13:169-185 (1988) describe a goodcorrelation between the in vitro octanol/water (O/W) partitioncoefficient and skin permeability and recommend those active ingredientswhose partition coefficient is about 100 (log P=2) as candidates fortransdermal administration. Likewise, Guy, Fundam. Appl. Toxicol. 17:575-583(1991) shows a parabola-like dependence between the logarithm ofthe maximum penetration rate and the logarithm of the octanol/waterpartition coefficient with an apex maximum at log P=2. Therefore, itappears that molecules with an O/W PC log P of about 2 should be goodcandidates for transdermal delivery.

Without wishing to be tied to a theory, it is believed that thepartition coefficient of the charged curcumin prodrug will be within arange that is highly favorable for transdermal delivery. It is notedthat native curcumin has an O/W partition coefficient of about log P=3,and that converting DHEA into its PRO2 prodrug reduced the O/W partitioncoefficient of DHEA from log P=1.54 to log P=0.79 (i.e., a reduction inlog P of about 0.75). If modifying curcumin with the trimethylglycinatemoiety has the same effect upon curcumin lipophilicity as it had forDHEA, then the log P O/W partition coefficient of the trimethylglycinatecurcumin should be about log P=2.5. Since this value is close to thetransdermal delivery optimum of about log P=2, it appears that curcuminglycinate prodrugs with an O/W partition coefficient log P of about 2.5should be good candidates for transdermal delivery.

Therefore, in some embodiments of the present invention the curcuminoidprodrug has a log P O/W partition coefficient of between about 1 and 3,preferably between about 1.5 and 2.5, more preferably between 1.7 and2.3.

A typical iontophoretic device for administering the prodrug of thepresent invention is provided in FIG. 23. An iontophoretic drug deliverysystem is generally composed of four basic components: a power source(typically batteries), control circuitry, electrodes, and twoelectrolyte-containing reservoirs. Using FIG. 23 as an example, in aconventional arrangement, two electrodes are disposed so as to be inintimate contact with the skin of a subject, as illustrated by 11 and13, the anode and cathode, respectively. Both electrodes are placedwithin a given skin region of the subject. One electrode is in contactwith a reservoir containing the prodrug or donor reservoir 15, and theother is contained within a ground reservoir 17 containing abiocompatible electrolyte solution, such as sodium chloride. In thefigure, the charged curcumin prodrug is designated as “CUR-GLY⁺ A⁻”,with “CUR-GLY⁺” representing the charged curcumin ester portion of thecomplex. In the figure, “K” is the complex counterion.

The electrode in contact with the prodrug is generally referred to asthe “active” electrode 11. The active electrode is the one from whichthe prodrug is driven into the body by application of an electricgradient. In a preferred embodiment of the present invention, theprodrug is a positively charged quaternary ammonium derivative ofcurcumin and the active electrode is the anode. For iontophoreticdelivery of curcumin prodrugs which are negatively charged, the activeelectrode is the cathode.

The other electrode, contained within a second reservoir, is oftenreferred to as the ground electrode 13, and serves to close theelectrical circuit through the body. In some instances, delivery of thesame drug out of both reservoirs in an alternating fashion can becarried out by periodically reversing the polarity of the electrodes.

A variety of electrode materials may be used in the iontophoreticdelivery device, and range from materials such as platinum tosilver-silver chloride. The choice of electrode will depend on thenature of the prodrug to be administered, among other considerations.

The active reservoir 15 will typically contain a solution of the prodrugspecies to be driven transdermally into the subject (including both theactive species and accompanying counterions). The prodrug may becontained within an aqueous solution, or within a hydrophilic gel or gelmatrix. In some instances, the active reservoir will contain the prodrugas a semi-solid, foam, or formulated with an absorbent material. Theground reservoir may similarly contain salt ions in an aqueous solution,or within a polymeric matrix.

Typically, the active reservoir will also contain buffers to maintainthe reservoir environment at the same charge as the electrode. In mostcases, a buffer possessing an opposite charge to the active prodrug willbe employed. In some instances, depending on the counterion of theprodrug salt, the prodrug salt may act as its own buffer. In general, toachieve the highest transport efficiency, the concentration of all ionicspecies, with the exception of the curcumin prodrug, is minimized.

In some embodiments of the invention, the iontophoretic device willoptionally contain a selectively permeable membrane. The membrane may belocated in a region separating the two reservoirs, or alternatively, mayseparate the contents of the active reservoir from the skin surface.Suitable materials for providing such membranes include natural andsynthetic polymers.

In iontophoretically administering a curcumin/chemical modifier complexto a subject, the circuit is completed by connection of the twoelectrodes to a source of electrical energy 19, such as a battery. Anelectronic control module is utilized to control the applied current,and in some cases, may comprise an integrated circuit, which would allowfor varying time intervals or feedback-controlled drug delivery.

Transdermal iontophoretic delivery is accomplished by application of anelectric current. In iontophoretic administration, the drug or prodrugdelivery rate is proportional to the amount of current applied.

In iontophoretically administering a charged curcumin prodrug of thepresent invention, an appropriate current intensity is selected which isbelow the pain threshold of the subject. The current should be withincomfortable toleration of the patient, with a current density which istypically less than 0.5 mA/cm² of the electrode surface. The current isthen applied for an appropriate length of time.

In a preferred embodiment of the invention, upon application of electricpotential, positively charged prodrug ions at the active electrode (inthis case, the anode) are driven from the donor reservoir, through theskin, and into the body. Simultaneously, negatively charged ions in thebody of the subject will migrate from the body and into the donorreservoir. At the ground electrode (cathode in this case), negativelycharged ions are driven into the skin, while positively charged ionsfrom the body of the subject migrate into the ground reservoir. In orderto maintain charge neutrality, oxidation occurs at the positiveelectrode and reduction at the negative electrode, as ions migrate fromone side of skin to the other. Upon transport of the complex across theskin and into the bloodstream, cleavage occurs to release the parentcurcumin in its active form.

1. An iontophoretic drug delivery system comprising: a) a power source,b) an anode and a cathode in electrical connection with the powersource, and c) a first electrolyte-containing reservoir in electricalconnection with the anode, and d) a second electrolyte-containingreservoir in electrical connection with the cathode, wherein one of thereservoirs contains a charged curcuminoid prodrug.
 2. The system ofclaim 1 wherein the charged curcuminoid prodrug comprises a glycinatemoiety.
 3. The system of claim 1 wherein the curcuminoid comprisesbisdemethoxycurcumin.
 4. The system of claim 1 wherein the curcuminoidis a hybrid of curcumin and resveratrol.
 5. The system of claim 1wherein the curcuminoid is a hybrid of bisdemethoxycurcumin andresveratrol.
 6. The system of claim 1 wherein the curcuminoid is ahybrid of curcumin and 3,3′,4′ fisetin.
 7. The system of claim 1 whereinthe curcuminoid is a hybrid of bisdemethoxycurcumin and 3,3′,4′ fisetin.8. The system of claim 1 wherein the curcuminoid is a hybrid of curcuminand honokiol.
 9. The system of claim 1 wherein the curcuminoid is ahybrid of bisdemethoxycurcumin and honokiol.